From eb3891557a2b417d5594009cb53924d1210e183c Mon Sep 17 00:00:00 2001
From: Henry Coles <henry@pitest.org>
Date: Thu, 3 Aug 2023 12:08:18 +0100
Subject: [PATCH] explicitly order history file entries

---
 .../tooling/MutationCoverage.java             | 12 ++++++--
 .../tooling/MutationCoverageReportTest.java   | 29 ++++++++++++++++++-
 2 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/pitest-entry/src/main/java/org/pitest/mutationtest/tooling/MutationCoverage.java b/pitest-entry/src/main/java/org/pitest/mutationtest/tooling/MutationCoverage.java
index e50402464..3818414f7 100644
--- a/pitest-entry/src/main/java/org/pitest/mutationtest/tooling/MutationCoverage.java
+++ b/pitest-entry/src/main/java/org/pitest/mutationtest/tooling/MutationCoverage.java
@@ -67,6 +67,7 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.Comparator;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Optional;
@@ -289,9 +290,14 @@ private MutationResultInterceptor resultInterceptor() {
   }
 
   private void recordClassPath(HistoryStore history, CoverageDatabase coverageData) {
-    final Set<ClassName> allClassNames = getAllClassesAndTests(coverageData);
-    final Collection<HierarchicalClassId> ids = FCollection.map(
-        this.code.getClassInfo(allClassNames), ClassInfo::getHierarchicalId);
+    Set<ClassName> allClassNames = getAllClassesAndTests(coverageData);
+
+    // sort by classname to ensure order consistent across machines
+    List<HierarchicalClassId> ids = this.code.getClassInfo(allClassNames).stream()
+            .map(ClassInfo::getHierarchicalId)
+            .sorted(Comparator.comparing(HierarchicalClassId::getName))
+            .collect(Collectors.toList());
+
     history.recordClassPath(ids, coverageData);
   }
 
diff --git a/pitest-entry/src/test/java/org/pitest/mutationtest/tooling/MutationCoverageReportTest.java b/pitest-entry/src/test/java/org/pitest/mutationtest/tooling/MutationCoverageReportTest.java
index b2578b33b..15a333540 100644
--- a/pitest-entry/src/test/java/org/pitest/mutationtest/tooling/MutationCoverageReportTest.java
+++ b/pitest-entry/src/test/java/org/pitest/mutationtest/tooling/MutationCoverageReportTest.java
@@ -14,6 +14,7 @@
  */
 package org.pitest.mutationtest.tooling;
 
+import static java.util.Arrays.asList;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.fail;
 import static org.mockito.ArgumentMatchers.anyCollection;
@@ -163,7 +164,33 @@ public void shouldRecordClassPath() {
 
     createAndRunTestee();
 
-    verify(this.history).recordClassPath(Arrays.asList(fooId), this.coverageDb);
+    verify(this.history).recordClassPath(asList(fooId), this.coverageDb);
+  }
+
+  @Test
+  public void ordersHistoryEntries() {
+
+    final ClassName clazz = ClassName.fromClass(Foo.class);
+
+    final HierarchicalClassId fooId = new HierarchicalClassId(
+            new ClassIdentifier(0, clazz), "0");
+    final HierarchicalClassId barId = new HierarchicalClassId(
+            new ClassIdentifier(0, ClassName.fromString("Bar")), "0");
+    final ClassInfo foo = ClassInfoMother.make(fooId.getId());
+    final ClassInfo bar = ClassInfoMother.make(barId.getId());
+
+    when(this.mutater.findMutations(ClassName.fromClass(Foo.class))).thenReturn(aMutantIn(Foo.class));
+
+    when(this.code.getCodeUnderTestNames()).thenReturn(
+            Collections.singleton(clazz));
+    when(this.code.getClassInfo(anyCollection())).thenReturn(
+           asList(foo, bar));
+    when(this.coverageDb.getCodeLinesForClass(clazz)).thenReturn(new ClassLines(clazz, Collections.emptySet()));
+
+    createAndRunTestee();
+
+    // bar comes first alphabetically
+    verify(this.history).recordClassPath(asList(barId, fooId), this.coverageDb);
   }
 
   @Test