1 files changed, 89 insertions, 0 deletions
diff --git a/controller-api/src/test/java/com/yahoo/vespa/hosted/controller/api/integration/billing/StatusHistoryTest.java b/controller-api/src/test/java/com/yahoo/vespa/hosted/controller/api/integration/billing/StatusHistoryTest.java
new file mode 100644
index 00000000000..46a4c7e199c
--- /dev/null
+++ b/controller-api/src/test/java/com/yahoo/vespa/hosted/controller/api/integration/billing/StatusHistoryTest.java
@@ -0,0 +1,89 @@
+package com.yahoo.vespa.hosted.controller.api.integration.billing;
+
+import org.junit.jupiter.api.Test;
+
+import java.time.Clock;
+import java.time.ZonedDateTime;
+import java.util.Map;
+import java.util.SortedMap;
+import java.util.TreeMap;
+
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+/**
+ * @author gjoranv
+ */
+public class StatusHistoryTest {
+
+    private final Clock clock = Clock.systemUTC();
+
+    @Test
+    void open_can_change_to_any_status() {
+        var history = StatusHistory.open(clock);
+        history.checkValidTransition(BillStatus.FROZEN);
+        history.checkValidTransition(BillStatus.CLOSED);
+        history.checkValidTransition(BillStatus.VOID);
+    }
+
+    @Test
+    void frozen_cannot_change_to_open() {
+        var history = new StatusHistory(historyWith(BillStatus.FROZEN));
+
+        history.checkValidTransition(BillStatus.CLOSED);
+        history.checkValidTransition(BillStatus.VOID);
+
+        assertThrows(IllegalArgumentException.class, () -> history.checkValidTransition(BillStatus.OPEN));
+    }
+
+    @Test
+    void closed_cannot_change() {
+        var history = new StatusHistory(historyWith(BillStatus.CLOSED));
+
+        assertThrows(IllegalArgumentException.class, () -> history.checkValidTransition(BillStatus.OPEN));
+        assertThrows(IllegalArgumentException.class, () -> history.checkValidTransition(BillStatus.FROZEN));
+        assertThrows(IllegalArgumentException.class, () -> history.checkValidTransition(BillStatus.VOID));
+    }
+
+    @Test
+    void void_cannot_change() {
+        var history = new StatusHistory(historyWith(BillStatus.VOID));
+
+        assertThrows(IllegalArgumentException.class, () -> history.checkValidTransition(BillStatus.OPEN));
+        assertThrows(IllegalArgumentException.class, () -> history.checkValidTransition(BillStatus.FROZEN));
+        assertThrows(IllegalArgumentException.class, () -> history.checkValidTransition(BillStatus.CLOSED));
+    }
+
+    @Test
+    void any_status_can_change_to_itself() {
+        var history = new StatusHistory(historyWith(BillStatus.OPEN));
+        history.checkValidTransition(BillStatus.OPEN);
+
+        history = new StatusHistory(historyWith(BillStatus.FROZEN));
+        history.checkValidTransition(BillStatus.FROZEN);
+
+        history = new StatusHistory(historyWith(BillStatus.CLOSED));
+        history.checkValidTransition(BillStatus.CLOSED);
+
+        history = new StatusHistory(historyWith(BillStatus.VOID));
+        history.checkValidTransition(BillStatus.VOID);
+    }
+
+    @Test
+    void it_validates_status_history_in_constructor() {
+        assertThrows(IllegalArgumentException.class, () -> new StatusHistory(historyWith(BillStatus.FROZEN, BillStatus.OPEN)));
+        assertThrows(IllegalArgumentException.class, () -> new StatusHistory(historyWith(BillStatus.CLOSED, BillStatus.OPEN)));
+        assertThrows(IllegalArgumentException.class, () -> new StatusHistory(historyWith(BillStatus.CLOSED, BillStatus.FROZEN)));
+        assertThrows(IllegalArgumentException.class, () -> new StatusHistory(historyWith(BillStatus.CLOSED, BillStatus.VOID)));
+        assertThrows(IllegalArgumentException.class, () -> new StatusHistory(historyWith(BillStatus.VOID, BillStatus.OPEN)));
+        assertThrows(IllegalArgumentException.class, () -> new StatusHistory(historyWith(BillStatus.VOID, BillStatus.FROZEN)));
+        assertThrows(IllegalArgumentException.class, () -> new StatusHistory(historyWith(BillStatus.VOID, BillStatus.CLOSED)));
+    }
+
+    private SortedMap<ZonedDateTime, BillStatus> historyWith(BillStatus... statuses) {
+        var history = new TreeMap<>(Map.of(ZonedDateTime.now(clock), BillStatus.OPEN));
+        for (var status : statuses) {
+            history.put(ZonedDateTime.now(clock), status);
+        }
+        return history;
+    }
+}