Revert "Jonmv/leaner token buffer"

9 files changed, 327 insertions, 666 deletions

diff --git a/document/src/main/java/com/yahoo/document/json/JsonReader.java b/document/src/main/java/com/yahoo/document/json/JsonReader.java
index 08d1fe688ed..3e1743b8d45 100644
--- a/document/src/main/java/com/yahoo/document/json/JsonReader.java
+++ b/document/src/main/java/com/yahoo/document/json/JsonReader.java
@@ -18,7 +18,6 @@ import java.io.InputStream;
 import java.util.Optional;
 
 import static com.yahoo.document.json.JsonReader.ReaderState.END_OF_FEED;
-import static com.yahoo.document.json.document.DocumentParser.FIELDS;
 import static com.yahoo.document.json.readers.JsonParserHelpers.expectArrayStart;
 
 /**
@@ -61,7 +60,7 @@ public class JsonReader {
      * @param docIdString document ID
      * @return the parsed document operation
      */
-    ParsedDocumentOperation readSingleDocument(DocumentOperationType operationType, String docIdString) {
+    public ParsedDocumentOperation readSingleDocument(DocumentOperationType operationType, String docIdString) {
         DocumentId docId = new DocumentId(docIdString);
         DocumentParseInfo documentParseInfo;
         try {
@@ -79,54 +78,6 @@ public class JsonReader {
         return operation;
     }
 
-    /**
-     * Reads a JSON which is expected to contain only the "fields" object of a document,
-     * and where other parameters, like the document ID and operation type, are supplied by other means.
-     *
-     * @param operationType the type of operation (update or put)
-     * @param docIdString document ID
-     * @return the parsed document operation
-     */
-    public ParsedDocumentOperation readSingleDocumentStreaming(DocumentOperationType operationType, String docIdString) {
-        try {
-            DocumentId docId = new DocumentId(docIdString);
-            DocumentParseInfo documentParseInfo = new DocumentParseInfo();
-            documentParseInfo.documentId = docId;
-            documentParseInfo.operationType = operationType;
-
-            if (JsonToken.START_OBJECT != parser.nextValue())
-                throw new IllegalArgumentException("expected start of root object, got " + parser.currentToken());
-
-            parser.nextValue();
-            if ( ! FIELDS.equals(parser.getCurrentName()))
-                throw new IllegalArgumentException("expected field \"fields\", but got " + parser.getCurrentName());
-
-            if (JsonToken.START_OBJECT != parser.currentToken())
-                throw new IllegalArgumentException("expected start of \"fields\" object, got " + parser.currentToken());
-
-            documentParseInfo.fieldsBuffer = new LazyTokenBuffer(parser);
-            VespaJsonDocumentReader vespaJsonDocumentReader = new VespaJsonDocumentReader(typeManager.getIgnoreUndefinedFields());
-            ParsedDocumentOperation operation = vespaJsonDocumentReader.createDocumentOperation(
-                    getDocumentTypeFromString(documentParseInfo.documentId.getDocType(), typeManager), documentParseInfo);
-
-            if ( ! documentParseInfo.fieldsBuffer.isEmpty())
-                throw new IllegalArgumentException("expected all content to be consumed by document parsing, but " +
-                                                   documentParseInfo.fieldsBuffer.nesting() + " levels remain");
-
-            if (JsonToken.END_OBJECT != parser.currentToken())
-                throw new IllegalArgumentException("expected end of \"fields\" object, got " + parser.currentToken());
-            if (JsonToken.END_OBJECT != parser.nextToken())
-                throw new IllegalArgumentException("expected end of root object, got " + parser.currentToken());
-            if (null != parser.nextToken())
-                throw new IllegalArgumentException("expected end of input, got " + parser.currentToken());
-
-            return operation;
-        }
-        catch (IOException e) {
-            throw new IllegalArgumentException("failed parsing document", e);
-        }
-    }
-
     /** Returns the next document operation, or null if we have reached the end */
     public DocumentOperation next() {
         switch (state) {
diff --git a/document/src/main/java/com/yahoo/document/json/LazyTokenBuffer.java b/document/src/main/java/com/yahoo/document/json/LazyTokenBuffer.java
deleted file mode 100644
index 0fbdd0b28c7..00000000000
--- a/document/src/main/java/com/yahoo/document/json/LazyTokenBuffer.java
+++ /dev/null
@@ -1,64 +0,0 @@
-package com.yahoo.document.json;
-
-import com.fasterxml.jackson.core.JsonParser;
-import com.fasterxml.jackson.core.JsonToken;
-
-import java.io.IOException;
-import java.util.function.Supplier;
-
-/**
- * A {@link TokenBuffer} which only buffers tokens when needed, i.e., when peeking.
- *
- * @author jonmv
- */
-public class LazyTokenBuffer extends TokenBuffer {
-
-    private final JsonParser parser;
-
-    public LazyTokenBuffer(JsonParser parser) {
-        this.parser = parser;
-        try { addFromParser(parser); }
-        catch (IOException e) { throw new IllegalArgumentException("failed parsing document JSON", e); }
-        if (JsonToken.START_OBJECT != current())
-            throw new IllegalArgumentException("expected start of JSON object, but got " + current());
-        updateNesting(current());
-    }
-
-    void advance() {
-        super.advance();
-        if (tokens.isEmpty() && nesting() > 0) tokens.add(nextToken()); // Fill current token if needed and possible.
-    }
-
-    @Override
-    public Supplier<Token> lookahead() {
-        return new Supplier<>() {
-            int localNesting = nesting();
-            Supplier<Token> buffered = LazyTokenBuffer.super.lookahead();
-            @Override public Token get() {
-                if (localNesting == 0)
-                    return null;
-
-                Token token = buffered.get();
-                if (token == null) {
-                    token = nextToken();
-                    tokens.add(token);
-                }
-                localNesting += nestingOffset(token.token);
-                return token;
-            }
-        };
-    }
-
-    private Token nextToken() {
-        try {
-            JsonToken token = parser.nextValue();
-            if (token == null)
-                throw new IllegalStateException("no more JSON tokens");
-            return new Token(token, parser.getCurrentName(), parser.getText());
-        }
-        catch (IOException e) {
-            throw new IllegalArgumentException("failed reading document JSON", e);
-        }
-    }
-
-}
diff --git a/document/src/main/java/com/yahoo/document/json/TokenBuffer.java b/document/src/main/java/com/yahoo/document/json/TokenBuffer.java
index 3a48f71c4cd..dec84e46b77 100644
--- a/document/src/main/java/com/yahoo/document/json/TokenBuffer.java
+++ b/document/src/main/java/com/yahoo/document/json/TokenBuffer.java
@@ -1,16 +1,15 @@
 // Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.document.json;
 
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
 import com.fasterxml.jackson.core.JsonParser;
 import com.fasterxml.jackson.core.JsonToken;
 import com.google.common.base.Preconditions;
 
-import java.io.IOException;
-import java.util.ArrayDeque;
-import java.util.Deque;
-import java.util.Iterator;
-import java.util.function.Supplier;
-
 /**
  * Helper class to enable lookahead in the token stream.
  *
@@ -18,76 +17,101 @@ import java.util.function.Supplier;
  */
 public class TokenBuffer {
 
-    final Deque<Token> tokens = new ArrayDeque<>();
+    private final List<Token> tokens;
 
+    private int position = 0;
     private int nesting = 0;
 
-    public TokenBuffer() { }
+    public TokenBuffer() {
+        this(new ArrayList<>());
+    }
+
+    public TokenBuffer(List<Token> tokens) {
+        this.tokens = tokens;
+        if (tokens.size() > 0)
+            updateNesting(tokens.get(position).token);
+    }
 
     /** Returns whether any tokens are available in this */
-    public boolean isEmpty() { return tokens.isEmpty(); }
+    public boolean isEmpty() { return remaining() == 0; }
+
+    public JsonToken previous() {
+        updateNestingGoingBackwards(current());
+        position--;
+        return current();
+    }
+
+    /** Returns the current token without changing position, or null if none */
+    public JsonToken current() {
+        if (isEmpty()) return null;
+        Token token = tokens.get(position);
+        if (token == null) return null;
+        return token.token;
+    }
 
-    /** Returns the next token, or null, and updates the nesting count of this. */
     public JsonToken next() {
-        advance();
+        position++;
         JsonToken token = current();
         updateNesting(token);
         return token;
     }
 
-    void advance() {
-        tokens.poll();
-    }
-
-    /** Returns the current token without changing position, or null if none */
-    public JsonToken current() {
-        return isEmpty() ? null : tokens.peek().token;
+    /** Returns a given number of tokens ahead, or null if none */
+    public JsonToken peek(int ahead) {
+        if (tokens.size() <= position + ahead) return null;
+        return tokens.get(position + ahead).token;
     }
 
     /** Returns the current token name without changing position, or null if none */
     public String currentName() {
-        return isEmpty() ? null : tokens.peek().name;
+        if (isEmpty()) return null;
+        Token token = tokens.get(position);
+        if (token == null) return null;
+        return token.name;
     }
 
     /** Returns the current token text without changing position, or null if none */
     public String currentText() {
-        return isEmpty() ? null : tokens.peek().text;
+        if (isEmpty()) return null;
+        Token token = tokens.get(position);
+        if (token == null) return null;
+        return token.text;
     }
 
-    /**
-     * Returns a sequence of remaining tokens in this, or nulls when none remain.
-     * This may fill the token buffer, but not otherwise modify it.
-     */
-    public Supplier<Token> lookahead() {
-        Iterator<Token> iterator = tokens.iterator();
-        if (iterator.hasNext()) iterator.next();
-        return () -> iterator.hasNext() ? iterator.next() : null;
+    public int remaining() {
+        return tokens.size() - position;
     }
 
     private void add(JsonToken token, String name, String text) {
-        tokens.add(new Token(token, name, text));
+        tokens.add(tokens.size(), new Token(token, name, text));
     }
 
-    public void bufferObject(JsonParser parser) {
-        bufferJsonStruct(parser, JsonToken.START_OBJECT);
+    public void bufferObject(JsonToken first, JsonParser tokens) {
+        bufferJsonStruct(first, tokens, JsonToken.START_OBJECT);
     }
 
-    private void bufferJsonStruct(JsonParser parser, JsonToken firstToken) {
-        JsonToken token = parser.currentToken();
-        Preconditions.checkArgument(token == firstToken,
-                                    "Expected %s, got %s.", firstToken.name(), token);
-        updateNesting(token);
+    private void bufferJsonStruct(JsonToken first, JsonParser tokens, JsonToken firstToken) {
+        int localNesting = 0;
+        JsonToken t = first;
 
-        try {
-            for (int nesting = addFromParser(parser); nesting > 0; nesting += addFromParser(parser))
-                parser.nextValue();
+        Preconditions.checkArgument(first == firstToken,
+                "Expected %s, got %s.", firstToken.name(), t);
+        if (remaining() == 0) {
+            updateNesting(t);
         }
-        catch (IOException e) {
-            throw new IllegalArgumentException(e);
+        localNesting = storeAndPeekNesting(t, localNesting, tokens);
+        while (localNesting > 0) {
+            t = nextValue(tokens);
+            localNesting = storeAndPeekNesting(t, localNesting, tokens);
         }
     }
 
-    int nestingOffset(JsonToken token) {
+    private int storeAndPeekNesting(JsonToken t, int nesting, JsonParser tokens) {
+        addFromParser(t, tokens);
+        return nesting + nestingOffset(t);
+    }
+
+    private int nestingOffset(JsonToken token) {
         if (token == null) return 0;
         if (token.isStructStart()) {
             return 1;
@@ -98,23 +122,43 @@ public class TokenBuffer {
         }
     }
 
-    int addFromParser(JsonParser tokens) throws IOException {
-        add(tokens.currentToken(), tokens.getCurrentName(), tokens.getText());
-        return nestingOffset(tokens.currentToken());
+    private void addFromParser(JsonToken t, JsonParser tokens) {
+        try {
+            add(t, tokens.getCurrentName(), tokens.getText());
+        } catch (IOException e) {
+            throw new IllegalArgumentException(e);
+        }
+    }
+
+    private JsonToken nextValue(JsonParser tokens) {
+        try {
+            return tokens.nextValue();
+        } catch (IOException e) {
+            throw new IllegalArgumentException(e);
+        }
     }
 
-    void updateNesting(JsonToken token) {
+    private void updateNesting(JsonToken token) {
         nesting += nestingOffset(token);
     }
 
+    private void updateNestingGoingBackwards(JsonToken token) {
+        nesting -= nestingOffset(token);
+    }
+
     public int nesting() {
         return nesting;
     }
 
     public void skipToRelativeNesting(int relativeNesting) {
         int initialNesting = nesting();
-        do next();
-        while (nesting() > initialNesting + relativeNesting);
+        do {
+            next();
+        } while ( nesting() > initialNesting + relativeNesting);
+    }
+
+    public List<Token> rest() {
+        return tokens.subList(position, tokens.size());
     }
 
     public static final class Token {
diff --git a/document/src/main/java/com/yahoo/document/json/document/DocumentParser.java b/document/src/main/java/com/yahoo/document/json/document/DocumentParser.java
index aef7e1cffe2..74656762fe1 100644
--- a/document/src/main/java/com/yahoo/document/json/document/DocumentParser.java
+++ b/document/src/main/java/com/yahoo/document/json/document/DocumentParser.java
@@ -86,6 +86,16 @@ public class DocumentParser {
     private void handleIdentLevelOne(DocumentParseInfo documentParseInfo, boolean docIdAndOperationIsSetExternally)
             throws IOException {
         JsonToken currentToken = parser.getCurrentToken();
+        if (currentToken == JsonToken.VALUE_TRUE || currentToken == JsonToken.VALUE_FALSE) {
+            try {
+                if (CREATE_IF_NON_EXISTENT.equals(parser.getCurrentName())) {
+                    documentParseInfo.create = Optional.ofNullable(parser.getBooleanValue());
+                    return;
+                }
+            } catch (IOException e) {
+                throw new RuntimeException("Got IO exception while parsing document", e);
+            }
+        }
         if ((currentToken == JsonToken.VALUE_TRUE || currentToken == JsonToken.VALUE_FALSE) &&
                 CREATE_IF_NON_EXISTENT.equals(parser.getCurrentName())) {
             documentParseInfo.create = Optional.of(currentToken == JsonToken.VALUE_TRUE);
@@ -101,11 +111,12 @@ public class DocumentParser {
         }
     }
 
-    private void handleIdentLevelTwo(DocumentParseInfo documentParseInfo) {
+    private  void handleIdentLevelTwo(DocumentParseInfo documentParseInfo) {
         try {
+            JsonToken currentToken = parser.getCurrentToken();
             // "fields" opens a dictionary and is therefore on level two which might be surprising.
-            if (parser.currentToken() == JsonToken.START_OBJECT && FIELDS.equals(parser.getCurrentName())) {
-                documentParseInfo.fieldsBuffer.bufferObject(parser);
+            if (currentToken == JsonToken.START_OBJECT && FIELDS.equals(parser.getCurrentName())) {
+                documentParseInfo.fieldsBuffer.bufferObject(currentToken, parser);
                 processIndent();
             }
         } catch (IOException e) {
diff --git a/document/src/main/java/com/yahoo/document/json/readers/DocumentParseInfo.java b/document/src/main/java/com/yahoo/document/json/readers/DocumentParseInfo.java
index e859306f04d..2dce07cdbe6 100644
--- a/document/src/main/java/com/yahoo/document/json/readers/DocumentParseInfo.java
+++ b/document/src/main/java/com/yahoo/document/json/readers/DocumentParseInfo.java
@@ -8,7 +8,6 @@ import com.yahoo.document.json.TokenBuffer;
 import java.util.Optional;
 
 public class DocumentParseInfo {
-    public DocumentParseInfo() { }
     public DocumentId documentId;
     public Optional<Boolean> create = Optional.empty();
     public Optional<String> condition = Optional.empty();
diff --git a/document/src/main/java/com/yahoo/document/json/readers/TensorReader.java b/document/src/main/java/com/yahoo/document/json/readers/TensorReader.java
index 1fd4029b1a5..0b7b1ae9996 100644
--- a/document/src/main/java/com/yahoo/document/json/readers/TensorReader.java
+++ b/document/src/main/java/com/yahoo/document/json/readers/TensorReader.java
@@ -4,15 +4,13 @@ package com.yahoo.document.json.readers;
 import com.fasterxml.jackson.core.JsonToken;
 import com.yahoo.document.datatypes.TensorFieldValue;
 import com.yahoo.document.json.TokenBuffer;
-import com.yahoo.document.json.TokenBuffer.Token;
+import com.yahoo.slime.Inspector;
+import com.yahoo.slime.Type;
 import com.yahoo.tensor.IndexedTensor;
 import com.yahoo.tensor.MixedTensor;
 import com.yahoo.tensor.Tensor;
 import com.yahoo.tensor.TensorAddress;
 import com.yahoo.tensor.TensorType;
-import com.yahoo.tensor.TensorType.Dimension;
-
-import java.util.function.Supplier;
 
 import static com.yahoo.document.json.readers.JsonParserHelpers.*;
 import static com.yahoo.tensor.serialization.JsonFormat.decodeHexString;
@@ -39,43 +37,36 @@ public class TensorReader {
         Tensor.Builder builder = Tensor.Builder.of(tensorFieldValue.getDataType().getTensorType());
         expectOneOf(buffer.current(), JsonToken.START_OBJECT, JsonToken.START_ARRAY);
         int initNesting = buffer.nesting();
-        while (true) {
-            Supplier<Token> lookahead = buffer.lookahead();
-            Token next = lookahead.get();
-            if (TENSOR_CELLS.equals(next.name) && ! primitiveContent(next.token, lookahead.get().token)) {
-                buffer.next();
+        for (buffer.next(); buffer.nesting() >= initNesting; buffer.next()) {
+            if (TENSOR_CELLS.equals(buffer.currentName()) && ! primitiveContent(buffer)) {
                 readTensorCells(buffer, builder);
             }
-            else if (TENSOR_VALUES.equals(next.name) && builder.type().dimensions().stream().allMatch(Dimension::isIndexed)) {
-                buffer.next();
+            else if (TENSOR_VALUES.equals(buffer.currentName()) && builder.type().dimensions().stream().allMatch(d -> d.isIndexed())) {
                 readTensorValues(buffer, builder);
             }
-            else if (TENSOR_BLOCKS.equals(next.name)) {
-                buffer.next();
+            else if (TENSOR_BLOCKS.equals(buffer.currentName())) {
                 readTensorBlocks(buffer, builder);
             }
-            else if (TENSOR_TYPE.equals(next.name) && next.token == JsonToken.VALUE_STRING) {
-                buffer.next();
+            else if (TENSOR_TYPE.equals(buffer.currentName()) && buffer.current() == JsonToken.VALUE_STRING) {
                 // Ignore input tensor type
             }
-            else if (buffer.nesting() == initNesting && JsonToken.END_OBJECT == next.token) {
-                buffer.next();
-                break;
-            }
             else {
+                buffer.previous(); // Back up to the start of the enclosing block
                 readDirectTensorValue(buffer, builder);
-                break;
+                buffer.previous(); // ... and back up to the end of the enclosing block
             }
         }
         expectOneOf(buffer.current(), JsonToken.END_OBJECT, JsonToken.END_ARRAY);
         tensorFieldValue.assign(builder.build());
     }
 
-    static boolean primitiveContent(JsonToken current, JsonToken next) {
-        if (current.isScalarValue()) return true;
-        if (current == JsonToken.START_ARRAY) {
-            if (next == JsonToken.END_ARRAY) return false;
-            if (next.isScalarValue()) return true;
+    static boolean primitiveContent(TokenBuffer buffer) {
+        JsonToken cellsValue = buffer.current();
+        if (cellsValue.isScalarValue()) return true;
+        if (cellsValue == JsonToken.START_ARRAY) {
+            JsonToken firstArrayValue = buffer.peek(1);
+            if (firstArrayValue == JsonToken.END_ARRAY) return false;
+            if (firstArrayValue.isScalarValue()) return true;
         }
         return false;
     }
@@ -195,7 +186,7 @@ public class TensorReader {
         boolean hasIndexed = builder.type().dimensions().stream().anyMatch(TensorType.Dimension::isIndexed);
         boolean hasMapped = builder.type().dimensions().stream().anyMatch(TensorType.Dimension::isMapped);
 
-        if (isArrayOfObjects(buffer))
+        if (isArrayOfObjects(buffer, 0))
             readTensorCells(buffer, builder);
         else if ( ! hasMapped)
             readTensorValues(buffer, builder);
@@ -205,12 +196,10 @@ public class TensorReader {
             readTensorCells(buffer, builder);
     }
 
-    private static boolean isArrayOfObjects(TokenBuffer buffer) {
-        if (buffer.current() != JsonToken.START_ARRAY) return false;
-        Supplier<Token> lookahead = buffer.lookahead();
-        Token next;
-        while ((next = lookahead.get()).token == JsonToken.START_ARRAY) { }
-        return next.token == JsonToken.START_OBJECT;
+    private static boolean isArrayOfObjects(TokenBuffer buffer, int ahead) {
+        if (buffer.peek(ahead++) != JsonToken.START_ARRAY) return false;
+        if (buffer.peek(ahead) == JsonToken.START_ARRAY) return isArrayOfObjects(buffer, ahead); // nested array
+        return buffer.peek(ahead) == JsonToken.START_OBJECT;
     }
 
     private static TensorAddress readAddress(TokenBuffer buffer, TensorType type) {
diff --git a/document/src/main/java/com/yahoo/document/json/readers/VespaJsonDocumentReader.java b/document/src/main/java/com/yahoo/document/json/readers/VespaJsonDocumentReader.java
index c7303d31ea2..113b8732b23 100644
--- a/document/src/main/java/com/yahoo/document/json/readers/VespaJsonDocumentReader.java
+++ b/document/src/main/java/com/yahoo/document/json/readers/VespaJsonDocumentReader.java
@@ -238,7 +238,7 @@ public class VespaJsonDocumentReader {
                                  "Expected end of JSON struct (%s), got %s", expectedFinalToken, buffer.current());
         Preconditions.checkState(buffer.nesting() == 0, "Nesting not zero at end of operation");
         Preconditions.checkState(buffer.next() == null, "Dangling data at end of operation");
-        Preconditions.checkState(buffer.isEmpty(), "Dangling data at end of operation");
+        Preconditions.checkState(buffer.remaining() == 0, "Dangling data at end of operation");
     }
 
 }
diff --git a/document/src/test/java/com/yahoo/document/json/JsonReaderTestCase.java b/document/src/test/java/com/yahoo/document/json/JsonReaderTestCase.java
index 080528fea77..5a9f02c790d 100644
--- a/document/src/test/java/com/yahoo/document/json/JsonReaderTestCase.java
+++ b/document/src/test/java/com/yahoo/document/json/JsonReaderTestCase.java
@@ -2120,93 +2120,69 @@ public class JsonReaderTestCase {
     @Test
     public void tensor_modify_update_with_replace_operation() {
         assertTensorModifyUpdate("{{x:a,y:b}:2.0}", TensorModifyUpdate.Operation.REPLACE, "sparse_tensor",
-                                 """
-                                 {
-                                   "operation": "replace",
-                                   "cells": [
-                                     { "address": { "x": "a", "y": "b" }, "value": 2.0 }
-                                   ]
-                                 }""");
+                inputJson("{",
+                        "  'operation': 'replace',",
+                        "  'cells': [",
+                        "    { 'address': { 'x': 'a', 'y': 'b' }, 'value': 2.0 } ]}"));
     }
 
     @Test
     public void tensor_modify_update_with_add_operation() {
         assertTensorModifyUpdate("{{x:a,y:b}:2.0}", TensorModifyUpdate.Operation.ADD, "sparse_tensor",
-                                 """
-                                 {
-                                   "operation": "add",
-                                   "cells": [
-                                     { "address": { "x": "a", "y": "b" }, "value": 2.0 }
-                                   ]
-                                 }""");
+                inputJson("{",
+                        "  'operation': 'add',",
+                        "  'cells': [",
+                        "    { 'address': { 'x': 'a', 'y': 'b' }, 'value': 2.0 } ]}"));
     }
 
     @Test
     public void tensor_modify_update_with_multiply_operation() {
         assertTensorModifyUpdate("{{x:a,y:b}:2.0}", TensorModifyUpdate.Operation.MULTIPLY, "sparse_tensor",
-                                 """
-                                 {
-                                   "operation": "multiply",
-                                   "cells": [
-                                     { "address": { "x": "a", "y": "b" }, "value": 2.0 }
-                                   ]
-                                 }""");
+                inputJson("{",
+                        "  'operation': 'multiply',",
+                        "  'cells': [",
+                        "    { 'address': { 'x': 'a', 'y': 'b' }, 'value': 2.0 } ]}"));
     }
 
     @Test
     public void tensor_modify_update_with_create_non_existing_cells_true() {
         assertTensorModifyUpdate("{{x:a,y:b}:2.0}", TensorModifyUpdate.Operation.ADD, true, "sparse_tensor",
-                                 """
-                                 {
-                                   "operation": "add",
-                                   "create": true,
-                                   "cells": [
-                                     { "address": { "x": "a", "y": "b" }, "value": 2.0 }
-                                   ]
-                                 }""");
+                inputJson("{",
+                        "  'operation': 'add',",
+                        "  'create': true,",
+                        "  'cells': [",
+                        "    { 'address': { 'x': 'a', 'y': 'b' }, 'value': 2.0 } ]}"));
     }
 
     @Test
     public void tensor_modify_update_with_create_non_existing_cells_false() {
         assertTensorModifyUpdate("{{x:a,y:b}:2.0}", TensorModifyUpdate.Operation.ADD, false, "sparse_tensor",
-                                 """
-                                 {
-                                   "operation": "add",
-                                   "create": false,
-                                   "cells": [
-                                     { "address": { "x": "a", "y": "b" }, "value": 2.0 }
-                                   ]
-                                 }""");
+                inputJson("{",
+                        "  'operation': 'add',",
+                        "  'create': false,",
+                        "  'cells': [",
+                        "    { 'address': { 'x': 'a', 'y': 'b' }, 'value': 2.0 } ]}"));
     }
 
     @Test
     public void tensor_modify_update_treats_the_input_tensor_as_sparse() {
         // Note that the type of the tensor in the modify update is sparse (it only has mapped dimensions).
         assertTensorModifyUpdate("tensor(x{},y{}):{{x:0,y:0}:2.0, {x:1,y:2}:3.0}",
-                                 TensorModifyUpdate.Operation.REPLACE, "dense_tensor",
-                                 """
-                                 {
-                                   "operation": "replace",
-                                   "cells": [
-                                     { "address": { "x": "0", "y": "0" }, "value": 2.0 },
-                                     { "address": { "x": "1", "y": "2" }, "value": 3.0 }
-                                   ]
-                                 }""");
+                TensorModifyUpdate.Operation.REPLACE, "dense_tensor",
+                inputJson("{",
+                        "  'operation': 'replace',",
+                        "  'cells': [",
+                        "    { 'address': { 'x': '0', 'y': '0' }, 'value': 2.0 },",
+                        "    { 'address': { 'x': '1', 'y': '2' }, 'value': 3.0 } ]}"));
     }
 
     @Test
     public void tensor_modify_update_on_non_tensor_field_throws() {
         try {
-            JsonReader reader = createReader("""
-                                             {
-                                               "update": "id:unittest:smoke::doc1",
-                                               "fields": {
-                                                 "something": {
-                                                   "modify": {}
-                                                 }
-                                               }
-                                             }
-                                             """);
+            JsonReader reader = createReader(inputJson("{ 'update': 'id:unittest:smoke::doc1',",
+                                                       "  'fields': {",
+                                                       "    'something': {",
+                                                       "      'modify': {} }}}"));
             reader.readSingleDocument(DocumentOperationType.UPDATE, "id:unittest:smoke::doc1");
             fail("Expected exception");
         }
@@ -2220,125 +2196,95 @@ public class JsonReaderTestCase {
     public void tensor_modify_update_on_dense_unbound_tensor_throws() {
         illegalTensorModifyUpdate("Error in 'dense_unbound_tensor': A modify update cannot be applied to tensor types with indexed unbound dimensions. Field 'dense_unbound_tensor' has unsupported tensor type 'tensor(x[],y[])'",
                                   "dense_unbound_tensor",
-                                  """
-                                  {
-                                    "operation": "replace",
-                                    "cells": [
-                                      { "address": { "x": "0", "y": "0" }, "value": 2.0 }
-                                    ]
-                                  }""");
+                                  "{",
+                                  "  'operation': 'replace',",
+                                  "  'cells': [",
+                                  "    { 'address': { 'x': '0', 'y': '0' }, 'value': 2.0 } ]}");
     }
 
     @Test
     public void tensor_modify_update_on_sparse_tensor_with_single_dimension_short_form() {
-        assertTensorModifyUpdate("{{x:a}:2.0, {x:c}: 3.0}", TensorModifyUpdate.Operation.REPLACE, "sparse_single_dimension_tensor",
-                                 """
-                                 {
-                                   "operation": "replace",
-                                   "cells": {
-                                     "a": 2.0,
-                                     "c": 3.0
-                                   }
-                                 }""");
+        assertTensorModifyUpdate("{{x:a}:2.0, {x:c}: 3.0}",  TensorModifyUpdate.Operation.REPLACE, "sparse_single_dimension_tensor",
+                                 inputJson("{",
+                                           "  'operation': 'replace',",
+                                           "  'cells': {",
+                                           "    'a': 2.0,",
+                                           "    'c': 3.0 }}"));
     }
 
     @Test
     public void tensor_modify_update_with_replace_operation_mixed() {
         assertTensorModifyUpdate("{{x:a,y:0}:2.0}", TensorModifyUpdate.Operation.REPLACE, "mixed_tensor",
-                                 """
-                                 {
-                                   "operation": "replace",
-                                   "cells": [
-                                     { "address": { "x": "a", "y": "0" }, "value": 2.0 }
-                                   ]
-                                 }""");
+                inputJson("{",
+                        "  'operation': 'replace',",
+                        "  'cells': [",
+                        "    { 'address': { 'x': 'a', 'y': '0' }, 'value': 2.0 } ]}"));
     }
 
     @Test
     public void tensor_modify_update_with_replace_operation_mixed_block_short_form_array() {
         assertTensorModifyUpdate("{{x:a,y:0}:1,{x:a,y:1}:2,{x:a,y:2}:3}", TensorModifyUpdate.Operation.REPLACE, "mixed_tensor",
-                                 """
-                                 {
-                                   "operation": "replace",
-                                   "blocks": [
-                                     { "address": { "x": "a" }, "values": [1,2,3] }
-                                   ]
-                                 }""");
+                                 inputJson("{",
+                                           "  'operation': 'replace',",
+                                           "  'blocks': [",
+                                           "    { 'address': { 'x': 'a' }, 'values': [1,2,3] } ]}"));
     }
 
     @Test
     public void tensor_modify_update_with_replace_operation_mixed_block_short_form_must_specify_full_subspace() {
         illegalTensorModifyUpdate("Error in 'mixed_tensor': At {x:a}: Expected 3 values, but got 2",
-                                  "mixed_tensor",
-                                  """
-                                  {
-                                    "operation": "replace",
-                                    "blocks": {
-                                      "a": [2,3]
-                                    }
-                                  }""");
+                                   "mixed_tensor",
+                                  inputJson("{",
+                                            "  'operation': 'replace',",
+                                            "  'blocks': {",
+                                            "    'a': [2,3] } }"));
     }
 
     @Test
     public void tensor_modify_update_with_replace_operation_mixed_block_short_form_map() {
         assertTensorModifyUpdate("{{x:a,y:0}:1,{x:a,y:1}:2,{x:a,y:2}:3}", TensorModifyUpdate.Operation.REPLACE, "mixed_tensor",
-                                 """
-                                 {
-                                   "operation": "replace",
-                                   "blocks": {
-                                     "a": [1,2,3]
-                                   }
-                                 }""");
+                                 inputJson("{",
+                                           "  'operation': 'replace',",
+                                           "  'blocks': {",
+                                           "    'a': [1,2,3] } }"));
     }
 
     @Test
     public void tensor_modify_update_with_add_operation_mixed() {
         assertTensorModifyUpdate("{{x:a,y:0}:2.0}", TensorModifyUpdate.Operation.ADD, "mixed_tensor",
-                                 """
-                                 {
-                                   "operation": "add",
-                                   "cells": [
-                                     { "address": { "x": "a", "y": "0" }, "value": 2.0 }
-                                   ]
-                                 }""");
+                inputJson("{",
+                        "  'operation': 'add',",
+                        "  'cells': [",
+                        "    { 'address': { 'x': 'a', 'y': '0' }, 'value': 2.0 } ]}"));
     }
 
     @Test
     public void tensor_modify_update_with_multiply_operation_mixed() {
         assertTensorModifyUpdate("{{x:a,y:0}:2.0}", TensorModifyUpdate.Operation.MULTIPLY, "mixed_tensor",
-                                 """
-                                 {
-                                   "operation": "multiply",
-                                   "cells": [
-                                     { "address": { "x": "a", "y": "0" }, "value": 2.0 }
-                                   ]
-                                 }""");
+                inputJson("{",
+                        "  'operation': 'multiply',",
+                        "  'cells': [",
+                        "    { 'address': { 'x': 'a', 'y': '0' }, 'value': 2.0 } ]}"));
     }
 
     @Test
     public void tensor_modify_update_with_out_of_bound_cells_throws() {
         illegalTensorModifyUpdate("Error in 'dense_tensor': Dimension 'y' has label '3' but type is tensor(x[2],y[3])",
                                   "dense_tensor",
-                                  """
-                                  {
-                                    "operation": "replace",
-                                    "cells": [
-                                      { "address": { "x": "0", "y": "3" }, "value": 2.0 }
-                                    ]
-                                  }""");
+                                  "{",
+                                  "  'operation': 'replace',",
+                                  "  'cells': [",
+                                  "    { 'address': { 'x': '0', 'y': '3' }, 'value': 2.0 } ]}");
     }
 
     @Test
     public void tensor_modify_update_with_out_of_bound_cells_throws_mixed() {
         illegalTensorModifyUpdate("Error in 'mixed_tensor': Dimension 'y' has label '3' but type is tensor(x{},y[3])",
                                   "mixed_tensor",
-                                  """
-                                  {
-                                    "operation": "replace",
-                                    "cells": [
-                                      { "address": { "x": "0", "y": "3" }, "value": 2.0 }
-                                    ]
-                                  }""");
+                                  "{",
+                                  "  'operation': 'replace',",
+                                  "  'cells': [",
+                                  "    { 'address': { 'x': '0', 'y': '3' }, 'value': 2.0 } ]}");
     }
 
 
@@ -2346,113 +2292,87 @@ public class JsonReaderTestCase {
     public void tensor_modify_update_with_unknown_operation_throws() {
         illegalTensorModifyUpdate("Error in 'sparse_tensor': Unknown operation 'unknown' in modify update for field 'sparse_tensor'",
                                   "sparse_tensor",
-                                  """
-                                  {
-                                    "operation": "unknown",
-                                    "cells": [
-                                      { "address": { "x": "a", "y": "b" }, "value": 2.0 }
-                                    ]
-                                  }""");
+                                  "{",
+                                  "  'operation': 'unknown',",
+                                   "  'cells': [",
+                                   "    { 'address': { 'x': 'a', 'y': 'b' }, 'value': 2.0 } ]}");
     }
 
     @Test
     public void tensor_modify_update_without_operation_throws() {
         illegalTensorModifyUpdate("Error in 'sparse_tensor': Modify update for field 'sparse_tensor' does not contain an operation",
                                   "sparse_tensor",
-                                  """
-                                  {
-                                    "cells": []
-                                  }""");
+                                  "{",
+                                  "  'cells': [] }");
     }
 
     @Test
     public void tensor_modify_update_without_cells_throws() {
         illegalTensorModifyUpdate("Error in 'sparse_tensor': Modify update for field 'sparse_tensor' does not contain tensor cells",
                                   "sparse_tensor",
-                                  """
-                                  {
-                                    "operation": "replace"
-                                  }""");
+                                  "{",
+                                  "  'operation': 'replace' }");
     }
 
     @Test
     public void tensor_modify_update_with_unknown_content_throws() {
         illegalTensorModifyUpdate("Error in 'sparse_tensor': Unknown JSON string 'unknown' in modify update for field 'sparse_tensor'",
                                   "sparse_tensor",
-                                  """
-                                  {
-                                    "unknown": "here"
-                                  }""");
+                                  "{",
+                                  "  'unknown': 'here' }");
     }
 
     @Test
     public void tensor_add_update_on_sparse_tensor() {
         assertTensorAddUpdate("{{x:a,y:b}:2.0, {x:c,y:d}: 3.0}", "sparse_tensor",
-                              """
-                              {
-                                "cells": [
-                                  { "address": { "x": "a", "y": "b" }, "value": 2.0 },
-                                  { "address": { "x": "c", "y": "d" }, "value": 3.0 }
-                                ]
-                              }""");
+                inputJson("{",
+                        "  'cells': [",
+                        "    { 'address': { 'x': 'a', 'y': 'b' }, 'value': 2.0 },",
+                        "    { 'address': { 'x': 'c', 'y': 'd' }, 'value': 3.0 } ]}"));
     }
 
     @Test
     public void tensor_add_update_on_sparse_tensor_with_single_dimension_short_form() {
         assertTensorAddUpdate("{{x:a}:2.0, {x:c}: 3.0}", "sparse_single_dimension_tensor",
-                              """
-                              {
-                                "cells": {
-                                  "a": 2.0,
-                                  "c": 3.0
-                                }
-                              }""");
+                              inputJson("{",
+                                        "  'cells': {",
+                                        "    'a': 2.0,",
+                                        "    'c': 3.0 }}"));
     }
 
     @Test
     public void tensor_add_update_on_mixed_tensor() {
         assertTensorAddUpdate("{{x:a,y:0}:2.0, {x:a,y:1}:3.0, {x:a,y:2}:0.0}", "mixed_tensor",
-                              """
-                              {
-                                "cells": [
-                                  { "address": { "x": "a", "y": "0" }, "value": 2.0 },
-                                  { "address": { "x": "a", "y": "1" }, "value": 3.0 }
-                                ]
-                              }""");
+                inputJson("{",
+                        "  'cells': [",
+                        "    { 'address': { 'x': 'a', 'y': '0' }, 'value': 2.0 },",
+                        "    { 'address': { 'x': 'a', 'y': '1' }, 'value': 3.0 } ]}"));
     }
 
     @Test
     public void tensor_add_update_on_mixed_with_out_of_bound_dense_cells_throws() {
         illegalTensorAddUpdate("Error in 'mixed_tensor': Index 3 out of bounds for length 3",
                                "mixed_tensor",
-                               """
-                               {
-                                 "cells": [
-                                   { "address": { "x": "0", "y": "3" }, "value": 2.0 }
-                                 ]
-                               }""");
+                               "{",
+                               "  'cells': [",
+                               "    { 'address': { 'x': '0', 'y': '3' }, 'value': 2.0 } ]}");
     }
 
     @Test
     public void tensor_add_update_on_dense_tensor_throws() {
         illegalTensorAddUpdate("Error in 'dense_tensor': An add update can only be applied to tensors with at least one sparse dimension. Field 'dense_tensor' has unsupported tensor type 'tensor(x[2],y[3])'",
                                "dense_tensor",
-                               """
-                               {
-                                 "cells": [ ]
-                               }""");
+                               "{",
+                               "  'cells': [] }");
     }
 
     @Test
     public void tensor_add_update_on_not_fully_specified_cell_throws() {
         illegalTensorAddUpdate("Error in 'sparse_tensor': Missing a label for dimension 'y' for tensor(x{},y{})",
                                "sparse_tensor",
-                               """
-                               {
-                                 "cells": [
-                                   { "address": { "x": "a" }, "value": 2.0 }
-                                 ]
-                               }""");
+                               "{",
+                               "  'cells': [",
+                               "    { 'address': { 'x': 'a' }, 'value': 2.0 } ]}");
     }
 
     @Test
@@ -2468,176 +2388,146 @@ public class JsonReaderTestCase {
     @Test
     public void tensor_remove_update_on_sparse_tensor() {
         assertTensorRemoveUpdate("{{x:a,y:b}:1.0,{x:c,y:d}:1.0}", "sparse_tensor",
-                                 """
-                                 {
-                                   "addresses": [
-                                     { "x": "a", "y": "b" },
-                                     { "x": "c", "y": "d" }
-                                   ]
-                                 }""");
+                inputJson("{",
+                        "  'addresses': [",
+                        "    { 'x': 'a', 'y': 'b' },",
+                        "    { 'x': 'c', 'y': 'd' } ]}"));
     }
 
     @Test
     public void tensor_remove_update_on_mixed_tensor() {
         assertTensorRemoveUpdate("{{x:1}:1.0,{x:2}:1.0}", "mixed_tensor",
-                                 """
-                                 {
-                                   "addresses": [
-                                     { "x": "1" },
-                                     { "x": "2" }
-                                   ]
-                                 }""");
+                inputJson("{",
+                        "  'addresses': [",
+                        "    { 'x': '1' },",
+                        "    { 'x': '2' } ]}"));
     }
 
     @Test
     public void tensor_remove_update_on_sparse_tensor_with_not_fully_specified_address() {
         assertTensorRemoveUpdate("{{y:b}:1.0,{y:d}:1.0}", "sparse_tensor",
-                                 """
-                                 {
-                                   "addresses": [
-                                     { "y": "b" },
-                                     { "y": "d" }
-                                   ]
-                                 }""");
+                inputJson("{",
+                        "  'addresses': [",
+                        "    { 'y': 'b' },",
+                        "    { 'y': 'd' } ]}"));
     }
 
     @Test
     public void tensor_remove_update_on_mixed_tensor_with_not_fully_specified_address() {
         assertTensorRemoveUpdate("{{x:1,z:a}:1.0,{x:2,z:b}:1.0}", "mixed_tensor_adv",
-                                 """
-                                 {
-                                   "addresses": [
-                                     { "x": "1", "z": "a" },
-                                     { "x": "2", "z": "b" }
-                                   ]
-                                 }""");
+                inputJson("{",
+                        "  'addresses': [",
+                        "    { 'x': '1', 'z': 'a' },",
+                        "    { 'x': '2', 'z': 'b' } ]}"));
     }
 
     @Test
     public void tensor_remove_update_on_mixed_tensor_with_dense_addresses_throws() {
         illegalTensorRemoveUpdate("Error in 'mixed_tensor': Indexed dimension address 'y' should not be specified in remove update",
                                   "mixed_tensor",
-                                  """
-                                  {
-                                    "addresses": [
-                                      { "x": "1", "y": "0" },
-                                      { "x": "2", "y": "0" }
-                                    ]
-                                  }""");
+                                  "{",
+                                  "  'addresses': [",
+                                  "    { 'x': '1', 'y': '0' },",
+                                  "    { 'x': '2', 'y': '0' } ]}");
     }
 
     @Test
     public void tensor_remove_update_on_dense_tensor_throws() {
         illegalTensorRemoveUpdate("Error in 'dense_tensor': A remove update can only be applied to tensors with at least one sparse dimension. Field 'dense_tensor' has unsupported tensor type 'tensor(x[2],y[3])'",
                                   "dense_tensor",
-                                  """
-                                  {
-                                    "addresses": []
-                                  }""");
+                                  "{",
+                                  "  'addresses': [] }");
     }
 
     @Test
     public void tensor_remove_update_with_stray_dimension_throws() {
         illegalTensorRemoveUpdate("Error in 'sparse_tensor': tensor(x{},y{}) does not contain dimension 'foo'",
-                                  "sparse_tensor",
-                                  """
-                                  {
-                                    "addresses": [
-                                      { "x": "a", "foo": "b" }
-                                    ]
-                                  }""");
+                "sparse_tensor",
+                "{",
+                "  'addresses': [",
+                "    { 'x': 'a', 'foo': 'b' } ]}");
 
         illegalTensorRemoveUpdate("Error in 'sparse_tensor': tensor(x{}) does not contain dimension 'foo'",
-                                  "sparse_tensor",
-                                  """
-                                  {
-                                    "addresses": [
-                                      { "x": "c" },
-                                      { "x": "a", "foo": "b" }
-                                    ]
-                                  }""");
+                "sparse_tensor",
+                "{",
+                "  'addresses': [",
+                "    { 'x': 'c' },",
+                "    { 'x': 'a', 'foo': 'b' } ]}");
     }
 
     @Test
     public void tensor_remove_update_without_cells_throws() {
         illegalTensorRemoveUpdate("Error in 'sparse_tensor': Remove update for field 'sparse_tensor' does not contain tensor addresses",
                                   "sparse_tensor",
-                                  """
-                                  {
-                                    "addresses": []
-                                  }""");
+                                  "{'addresses': [] }");
 
         illegalTensorRemoveUpdate("Error in 'mixed_tensor': Remove update for field 'mixed_tensor' does not contain tensor addresses",
                                   "mixed_tensor",
-                                  """
-                                  {
-                                    "addresses": []
-                                  }""");
+                                  "{'addresses': [] }");
     }
 
     @Test
     public void require_that_parser_propagates_datatype_parser_errors_predicate() {
         assertParserErrorMatches(
                 "Error in document 'id:unittest:testpredicate::0' - could not parse field 'boolean' of type 'predicate': " +
-                "line 1:10 no viable alternative at character '>'",
-                """
-                [
-                  {
-                    "fields": {
-                      "boolean": "timestamp > 9000"
-                    },
-                    "put": "id:unittest:testpredicate::0"
-                  }
-                ]
-                """);
+                        "line 1:10 no viable alternative at character '>'",
+
+                "[",
+                "      {",
+                "          'fields': {",
+                "              'boolean': 'timestamp > 9000'",
+                "          },",
+                "          'put': 'id:unittest:testpredicate::0'",
+                "      }",
+                "]"
+        );
     }
 
     @Test
     public void require_that_parser_propagates_datatype_parser_errors_string_as_int() {
         assertParserErrorMatches(
                 "Error in document 'id:unittest:testint::0' - could not parse field 'integerfield' of type 'int': " +
-                "For input string: \" 1\"",
-                """
-                [
-                  {
-                    "fields": {
-                      "integerfield": " 1"
-                    },
-                    "put": "id:unittest:testint::0"
-                  }
-                ]
-                """);
+                        "For input string: \" 1\"",
+
+                "[",
+                "      {",
+                "          'fields': {",
+                "              'integerfield': ' 1'",
+                "          },",
+                "          'put': 'id:unittest:testint::0'",
+                "      }",
+                "]"
+        );
     }
 
     @Test
     public void require_that_parser_propagates_datatype_parser_errors_overflowing_int() {
         assertParserErrorMatches(
                 "Error in document 'id:unittest:testint::0' - could not parse field 'integerfield' of type 'int': " +
-                "For input string: \"281474976710656\"",
-                """
-                [
-                  {
-                    "fields": {
-                      "integerfield": 281474976710656
-                    },
-                    "put": "id:unittest:testint::0"
-                  }
-                ]
-                """);
+                        "For input string: \"281474976710656\"",
+
+                "[",
+                "      {",
+                "          'fields': {",
+                "              'integerfield': 281474976710656",
+                "          },",
+                "          'put': 'id:unittest:testint::0'",
+                "      }",
+                "]"
+        );
     }
 
     @Test
     public void requireThatUnknownDocTypeThrowsIllegalArgumentException() {
-        String jsonData = """
-                          [
-                            {
-                              "put": "id:ns:walrus::walrus1",
-                              "fields": {
-                                "aField": 42
-                              }
-                            }
-                          ]
-                          """;
+        final String jsonData = inputJson(
+                "[",
+                "      {",
+                "          'put': 'id:ns:walrus::walrus1',",
+                "          'fields': {",
+                "              'aField': 42",
+                "          }",
+                "      }",
+                "]");
         try {
             new JsonReader(types, jsonToInputStream(jsonData), parserFactory).next();
             fail();
@@ -2687,40 +2577,30 @@ public class JsonReaderTestCase {
         return createPutWithTensor(inputTensor, "sparse_tensor");
     }
     private DocumentPut createPutWithTensor(String inputTensor, String tensorFieldName) {
-        JsonReader streaming = createReader("""
-                                         {
-                                           "fields": {
-                                             "%s": %s
-                                           }
-                                         }
-                                         """.formatted(tensorFieldName, inputTensor));
-        DocumentPut lazyParsed = (DocumentPut) streaming.readSingleDocumentStreaming(DocumentOperationType.PUT, TENSOR_DOC_ID).operation();
-        JsonReader reader = createReader("""
-                                         [
-                                           {
-                                             "put": "%s",
-                                             "fields": {
-                                               "%s": %s
-                                             }
-                                           }
-                                         ]""".formatted(TENSOR_DOC_ID, tensorFieldName, inputTensor));
-        DocumentPut bufferParsed = (DocumentPut) reader.next();
-        assertEquals(lazyParsed, bufferParsed);
-        return bufferParsed;
+        JsonReader reader = createReader(inputJson("[",
+                "{ 'put': '" + TENSOR_DOC_ID + "',",
+                "  'fields': {",
+                "    '" + tensorFieldName + "': " + inputTensor + "  }}]"));
+        return (DocumentPut) reader.next();
     }
 
     private DocumentUpdate createAssignUpdateWithSparseTensor(String inputTensor) {
         return createAssignUpdateWithTensor(inputTensor, "sparse_tensor");
     }
     private DocumentUpdate createAssignUpdateWithTensor(String inputTensor, String tensorFieldName) {
-        return createTensorUpdate("assign", inputTensor, tensorFieldName);
+        JsonReader reader = createReader(inputJson("[",
+                "{ 'update': '" + TENSOR_DOC_ID + "',",
+                "  'fields': {",
+                "    '" + tensorFieldName + "': {",
+                "      'assign': " + (inputTensor != null ? inputTensor : "null") + " } } } ]"));
+        return (DocumentUpdate) reader.next();
     }
 
     private static Tensor assertSparseTensorField(String expectedTensor, DocumentPut put) {
         return assertTensorField(expectedTensor, put, "sparse_tensor");
     }
     private Tensor assertTensorField(String expectedTensor, String fieldName, String inputJson) {
-        return assertTensorField(expectedTensor, createPutWithTensor(inputJson(inputJson), fieldName), fieldName);
+        return assertTensorField(expectedTensor, createPutWithTensor(inputJson, fieldName), fieldName);
     }
     private static Tensor assertTensorField(String expectedTensor, DocumentPut put, String tensorFieldName) {
         return assertTensorField(Tensor.from(expectedTensor), put, tensorFieldName);
@@ -2793,29 +2673,12 @@ public class JsonReaderTestCase {
     }
 
     private DocumentUpdate createTensorUpdate(String operation, String tensorJson, String tensorFieldName) {
-        JsonReader streaming = createReader("""
-                                            {
-                                              "fields": {
-                                                "%s": {
-                                                   "%s": %s
-                                                }
-                                              }
-                                            }""".formatted(tensorFieldName, operation, tensorJson));
-        DocumentUpdate lazyParsed = (DocumentUpdate) streaming.readSingleDocumentStreaming(DocumentOperationType.UPDATE, TENSOR_DOC_ID).operation();
-        JsonReader reader = createReader("""
-                                         [
-                                           {
-                                             "update": "%s",
-                                             "fields": {
-                                               "%s": {
-                                                 "%s": %s
-                                               }
-                                             }
-                                           }
-                                         ]""".formatted(TENSOR_DOC_ID, tensorFieldName, operation, tensorJson));
-        DocumentUpdate bufferParsed = (DocumentUpdate) reader.next();
-        assertEquals(lazyParsed, bufferParsed);
-        return bufferParsed;
+        JsonReader reader = createReader(inputJson("[",
+                "{ 'update': '" + TENSOR_DOC_ID + "',",
+                "  'fields': {",
+                "    '" + tensorFieldName + "': {",
+                "      '" + operation + "': " + tensorJson + " }}}]"));
+        return (DocumentUpdate) reader.next();
     }
 
     private void assertTensorAddUpdate(String expectedTensor, String tensorFieldName, String tensorJson) {
diff --git a/document/src/test/java/com/yahoo/document/json/LazyTokenBufferTest.java b/document/src/test/java/com/yahoo/document/json/LazyTokenBufferTest.java
deleted file mode 100644
index 3ed2ed531c3..00000000000
--- a/document/src/test/java/com/yahoo/document/json/LazyTokenBufferTest.java
+++ /dev/null
@@ -1,132 +0,0 @@
-package com.yahoo.document.json;
-
-import com.fasterxml.jackson.core.JsonFactory;
-import com.fasterxml.jackson.core.JsonParser;
-import com.fasterxml.jackson.core.JsonToken;
-import com.yahoo.document.json.TokenBuffer.Token;
-import org.junit.Test;
-
-import java.io.IOException;
-import java.util.function.Supplier;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNull;
-
-/**
- * @author jonmv
- */
-public class LazyTokenBufferTest {
-
-    @Test
-    public void testBuffer() throws IOException {
-        String json = """
-                      {
-                        "fields": {
-                          "foo": "bar",
-                          "baz": [1, 2, 3],
-                          "quu": { "qux": null }
-                        }
-                      }""";
-        JsonParser parser = new JsonFactory().createParser(json);
-        parser.nextValue();
-        parser.nextValue();
-        assertEquals(JsonToken.START_OBJECT, parser.currentToken());
-        assertEquals("fields", parser.currentName());
-
-        // Peeking through the buffer doesn't change nesting.
-        LazyTokenBuffer buffer = new LazyTokenBuffer(parser);
-        assertEquals(JsonToken.START_OBJECT, buffer.current());
-        assertEquals("fields", buffer.currentName());
-        assertEquals(1, buffer.nesting());
-
-        Supplier<Token> lookahead = buffer.lookahead();
-        Token peek = lookahead.get();
-        assertEquals(JsonToken.VALUE_STRING, peek.token);
-        assertEquals("foo", peek.name);
-        assertEquals("bar", peek.text);
-        assertEquals(1, buffer.nesting());
-
-        peek = lookahead.get();
-        assertEquals(JsonToken.START_ARRAY, peek.token);
-        assertEquals("baz", peek.name);
-        assertEquals(1, buffer.nesting());
-
-        peek = lookahead.get();
-        assertEquals(JsonToken.VALUE_NUMBER_INT, peek.token);
-        assertEquals("1", peek.text);
-
-        peek = lookahead.get();
-        assertEquals(JsonToken.VALUE_NUMBER_INT, peek.token);
-        assertEquals("2", peek.text);
-
-        peek = lookahead.get();
-        assertEquals(JsonToken.VALUE_NUMBER_INT, peek.token);
-        assertEquals("3", peek.text);
-
-        peek = lookahead.get();
-        assertEquals(JsonToken.END_ARRAY, peek.token);
-        assertEquals(1, buffer.nesting());
-
-        peek = lookahead.get();
-        assertEquals(JsonToken.START_OBJECT, peek.token);
-        assertEquals("quu", peek.name);
-        assertEquals(1, buffer.nesting());
-
-        peek = lookahead.get();
-        assertEquals(JsonToken.VALUE_NULL, peek.token);
-        assertEquals("qux", peek.name);
-
-        peek = lookahead.get();
-        assertEquals(JsonToken.END_OBJECT, peek.token);
-        assertEquals(1, buffer.nesting());
-
-        peek = lookahead.get();
-        assertEquals(JsonToken.END_OBJECT, peek.token);
-        assertEquals(1, buffer.nesting());
-
-        peek = lookahead.get();
-        assertNull(peek);
-
-        // Parser is now at the end.
-        assertEquals(JsonToken.END_OBJECT, parser.nextToken());
-        assertNull(parser.nextToken());
-
-        // Repeat iterating through the buffer, this time advancing it, and see that nesting changes.
-        assertEquals(JsonToken.VALUE_STRING, buffer.next());
-        assertEquals("foo", buffer.currentName());
-        assertEquals("bar", buffer.currentText());
-        assertEquals(1, buffer.nesting());
-
-        assertEquals(JsonToken.START_ARRAY, buffer.next());
-        assertEquals("baz", buffer.currentName());
-        assertEquals(2, buffer.nesting());
-
-        assertEquals(JsonToken.VALUE_NUMBER_INT, buffer.next());
-        assertEquals("1", buffer.currentText());
-
-        assertEquals(JsonToken.VALUE_NUMBER_INT, buffer.next());
-        assertEquals("2", buffer.currentText());
-
-        assertEquals(JsonToken.VALUE_NUMBER_INT, buffer.next());
-        assertEquals("3", buffer.currentText());
-
-        assertEquals(JsonToken.END_ARRAY, buffer.next());
-        assertEquals(1, buffer.nesting());
-
-        assertEquals(JsonToken.START_OBJECT, buffer.next());
-        assertEquals("quu", buffer.currentName());
-        assertEquals(2, buffer.nesting());
-
-        assertEquals(JsonToken.VALUE_NULL, buffer.next());
-        assertEquals("qux", buffer.currentName());
-
-        assertEquals(JsonToken.END_OBJECT, buffer.next());
-        assertEquals(1, buffer.nesting());
-
-        assertEquals(JsonToken.END_OBJECT, buffer.next());
-        assertEquals(0, buffer.nesting());
-
-        assertNull(buffer.next());
-    }
-
-}