Add JSON normalize method to test helper

4 files changed, 226 insertions, 0 deletions

diff --git a/testutil/src/main/java/com/yahoo/test/json/JsonBuilder.java b/testutil/src/main/java/com/yahoo/test/json/JsonBuilder.java
new file mode 100644
index 00000000000..bbb8586a290
--- /dev/null
+++ b/testutil/src/main/java/com/yahoo/test/json/JsonBuilder.java
@@ -0,0 +1,75 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.test.json;
+
+import com.fasterxml.jackson.core.io.JsonStringEncoder;
+
+/**
+ * String buffer for building a formatted JSON.
+ *
+ * @author hakonhall
+ */
+class JsonBuilder {
+    private final JsonStringEncoder jsonStringEncoder = JsonStringEncoder.getInstance();
+    private final StringBuilder builder = new StringBuilder();
+    private final String indentation;
+    private final boolean multiLine;
+    private final String colon;
+
+    private boolean bol = true;
+    private int level = 0;
+
+    static JsonBuilder forCompactJson() { return new JsonBuilder(0, true); }
+    static JsonBuilder forMultiLineJson(int spacesPerIndent) { return new JsonBuilder(spacesPerIndent, false); }
+
+    JsonBuilder(int spacesPerIndent, boolean compact) {
+        this.indentation = compact ? "" : " ".repeat(spacesPerIndent);
+        this.multiLine = !compact;
+        this.colon = compact ? ":" : ": ";
+    }
+
+    void appendLineAndIndent(String text) { appendLineAndIndent(text, 0); }
+
+    void newLineIndentAndAppend(int levelShift, String text) {
+        appendNewLine();
+        indent(levelShift);
+        append(text);
+    }
+
+    void appendLineAndIndent(String text, int levelShift) {
+        appendLine(text);
+        indent(levelShift);
+        append("");
+    }
+
+    void appendColon() { builder.append(colon); }
+
+    void appendStringValue(String rawString) {
+        builder.append('"');
+        jsonStringEncoder.quoteAsString(rawString, builder);
+        builder.append('"');
+    }
+
+    void append(String textWithoutNewline) {
+        if (bol) {
+            builder.append(indentation.repeat(level));
+            bol = false;
+        }
+
+        builder.append(textWithoutNewline);
+    }
+
+    private void indent(int levelShift) { level += levelShift; }
+
+    private void appendLine(String text) {
+        append(text);
+        appendNewLine();
+    }
+
+    private void appendNewLine() {
+        if (multiLine) builder.append('\n');
+        bol = true;
+    }
+
+    @Override
+    public String toString() { return builder.toString(); }
+}
diff --git a/testutil/src/main/java/com/yahoo/test/json/JsonNodeFormatter.java b/testutil/src/main/java/com/yahoo/test/json/JsonNodeFormatter.java
new file mode 100644
index 00000000000..d0e07e66e0b
--- /dev/null
+++ b/testutil/src/main/java/com/yahoo/test/json/JsonNodeFormatter.java
@@ -0,0 +1,81 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.test.json;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Iterator;
+
+/**
+ * Formats a {@link JsonNode} to a normalized JSON string, see {@link JsonTestHelper}.
+ *
+ * @author hakonhall
+ */
+class JsonNodeFormatter {
+    private final JsonBuilder builder;
+
+    /** See {@link JsonTestHelper}. */
+    static String toNormalizedJson(JsonNode jsonNode, boolean compact) {
+        JsonNodeFormatter formatter = new JsonNodeFormatter(compact);
+        formatter.appendValue(jsonNode);
+        return formatter.toString();
+    }
+
+    private JsonNodeFormatter(boolean compact) {
+        builder = compact ? JsonBuilder.forCompactJson() : JsonBuilder.forMultiLineJson(2);
+    }
+
+    private void appendValue(JsonNode jsonNode) {
+        switch (jsonNode.getNodeType()) {
+            case OBJECT -> {
+                ObjectNode objectNode = (ObjectNode) jsonNode;
+                ArrayList<String> fieldNames = new ArrayList<>();
+                objectNode.fieldNames().forEachRemaining(fieldNames::add);
+                Collections.sort(fieldNames);
+                if (fieldNames.isEmpty()) {
+                    builder.append("{}");
+                } else {
+                    boolean firstIteration = true;
+                    for (var fieldName : fieldNames) {
+                        if (firstIteration) {
+                            builder.appendLineAndIndent("{", +1);
+                            firstIteration = false;
+                        } else {
+                            builder.appendLineAndIndent(",");
+                        }
+
+                        builder.appendStringValue(fieldName);
+                        builder.appendColon();
+                        appendValue(objectNode.get(fieldName));
+                    }
+
+                    builder.newLineIndentAndAppend(-1, "}");
+                }
+            }
+            case ARRAY -> {
+                Iterator<JsonNode> elements = jsonNode.elements();
+                if (elements.hasNext()) {
+                    builder.appendLineAndIndent("[", +1);
+                    appendValue(elements.next());
+
+                    while (elements.hasNext()) {
+                        builder.appendLineAndIndent(",");
+                        appendValue(elements.next());
+                    }
+
+                    builder.newLineIndentAndAppend(-1, "]");
+                } else {
+                    builder.append("[]");
+                }
+            }
+            case BOOLEAN, NUMBER, NULL -> builder.append(jsonNode.asText());
+            case STRING -> builder.appendStringValue(jsonNode.asText());
+            case BINARY, MISSING, POJO -> throw new IllegalStateException(jsonNode.getNodeType().toString());
+        }
+    }
+
+    @Override
+    public String toString() { return builder.toString(); }
+}
diff --git a/testutil/src/main/java/com/yahoo/test/json/JsonTestHelper.java b/testutil/src/main/java/com/yahoo/test/json/JsonTestHelper.java
index f7112ee9379..589cc3ab4ef 100644
--- a/testutil/src/main/java/com/yahoo/test/json/JsonTestHelper.java
+++ b/testutil/src/main/java/com/yahoo/test/json/JsonTestHelper.java
@@ -17,6 +17,31 @@ public class JsonTestHelper {
     private static final ObjectMapper mapper = new ObjectMapper();
 
     /**
+     * Returns a normalized JSON String.
+     *
+     * <ol>
+     *     <li>A JSON string with each object's names in sorted order.</li>
+     *     <li>Two JSONs are equal iff their normalized JSON strings are equal.*</li>
+     *     <li>The normalized JSON is (by default) an indented multi-line string to facilitate
+     *     readability and line-based diff tools.</li>
+     *     <li>The normalized string does not end with a newline (\n).</li>
+     * </ol>
+     *
+     * <p>*) No effort is done to normalize decimals and may cause false non-equality,
+     * e.g. 1.2e1 is not equal to 12.  This may be fixed at a later time if needed.</p>
+     */
+    public static String normalize(String json) {
+        JsonNode jsonNode;
+        try {
+            jsonNode = mapper.readTree(json);
+        } catch (JsonProcessingException e) {
+            throw new IllegalArgumentException("Invalid JSON", e);
+        }
+
+        return JsonNodeFormatter.toNormalizedJson(jsonNode, false);
+    }
+
+    /**
      * Convenience method to input JSON without escaping double quotes and newlines
      * Each parameter represents a line of JSON encoded data
      * The lines are joined with newline and single quotes are replaced with double quotes
diff --git a/testutil/src/test/java/com/yahoo/test/json/JsonTestHelperTest.java b/testutil/src/test/java/com/yahoo/test/json/JsonTestHelperTest.java
new file mode 100644
index 00000000000..d0798284da1
--- /dev/null
+++ b/testutil/src/test/java/com/yahoo/test/json/JsonTestHelperTest.java
@@ -0,0 +1,45 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.test.json;
+
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+/**
+ * @author hakonhall
+ */
+public class JsonTestHelperTest {
+    @Test
+    public void normalize() {
+        verifyNormalization("""
+                            {"a": 1, "c": 2,
+                              "b": [ {"n": 3, "m": 4}, 5 ]
+                            }
+                            """,
+                            """
+                            {
+                              "a": 1,
+                              "b": [
+                                {
+                                  "m": 4,
+                                  "n": 3
+                                },
+                                5
+                              ],
+                              "c": 2
+                            }""");
+
+        verifyNormalization("[1,2]", """
+                                     [
+                                       1,
+                                       2
+                                     ]""");
+
+        verifyNormalization("null", "null");
+        verifyNormalization("{ \n}", "{}");
+    }
+
+    private static void verifyNormalization(String json, String normalizedJson) {
+        assertEquals(normalizedJson, JsonTestHelper.normalize(json));
+    }
+}
\ No newline at end of file