Improve mutation testing setup

Summary of changes: - Enable Pitest's built-in `STRONGER` mutator group. - Enable Arcmutate's `EXTENDED` mutator group. - Enable Arcmutate's JUnit 5 Accelerator Plugin. - Modify `MoreTypesTest` such that it is impacted by mutations to the `MoreTypes` class. See: - https://pitest.org/quickstart/mutators/ - https://docs.arcmutate.com/docs/extended-operators.html - https://docs.arcmutate.com/docs/accelerator.html
PicnicSupermarket · Dec 3, 2022 · ddd67fa · ddd67fa
1 parent 5afa7e1
commit ddd67fa
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Showing 2 changed files with 64 additions and 43 deletions.
diff --git a/error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/util/MoreTypesTest.java b/error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/util/MoreTypesTest.java
@@ -25,46 +25,6 @@
 import org.junit.jupiter.api.Test;
 
 final class MoreTypesTest {
-  private static final ImmutableSet<Supplier<Type>> TYPES =
-      ImmutableSet.of(
-          // Invalid types.
-          type("java.lang.Nonexistent"),
-          generic(type("java.util.Integer"), unbound()),
-          // Valid types.
-          type("java.lang.String"),
-          type("java.lang.Number"),
-          superOf(type("java.lang.Number")),
-          subOf(type("java.lang.Number")),
-          type("java.lang.Integer"),
-          superOf(type("java.lang.Integer")),
-          subOf(type("java.lang.Integer")),
-          type("java.util.Optional"),
-          raw(type("java.util.Optional")),
-          generic(type("java.util.Optional"), unbound()),
-          generic(type("java.util.Optional"), type("java.lang.Number")),
-          type("java.util.Collection"),
-          raw(type("java.util.Collection")),
-          generic(type("java.util.Collection"), unbound()),
-          generic(type("java.util.Collection"), type("java.lang.Number")),
-          generic(type("java.util.Collection"), superOf(type("java.lang.Number"))),
-          generic(type("java.util.Collection"), subOf(type("java.lang.Number"))),
-          generic(type("java.util.Collection"), type("java.lang.Integer")),
-          generic(type("java.util.Collection"), superOf(type("java.lang.Integer"))),
-          generic(type("java.util.Collection"), subOf(type("java.lang.Integer"))),
-          type("java.util.List"),
-          raw(type("java.util.List")),
-          generic(type("java.util.List"), unbound()),
-          generic(type("java.util.List"), type("java.lang.Number")),
-          generic(type("java.util.List"), superOf(type("java.lang.Number"))),
-          generic(type("java.util.List"), subOf(type("java.lang.Number"))),
-          generic(type("java.util.List"), type("java.lang.Integer")),
-          generic(type("java.util.List"), superOf(type("java.lang.Integer"))),
-          generic(type("java.util.List"), subOf(type("java.lang.Integer"))),
-          generic(
-              type("java.util.Map"),
-              type("java.lang.String"),
-              subOf(generic(type("java.util.Collection"), superOf(type("java.lang.Short"))))));
-
   @Test
   void matcher() {
     CompilationTestHelper.newInstance(SubtypeFlagger.class, getClass())
@@ -159,8 +119,8 @@ void matcher() {
   }
 
   /**
-   * A {@link BugChecker} that flags method invocations that are a subtype of any type contained in
-   * {@link #TYPES}.
+   * A {@link BugChecker} that flags method invocations that are a subtype of any type defined by
+   * {@link #getTestTypes()}.
    */
   @BugPattern(summary = "Flags invocations of methods with select return types", severity = ERROR)
   public static final class SubtypeFlagger extends BugChecker
@@ -173,7 +133,7 @@ public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState
 
       List<String> matches = new ArrayList<>();
 
-      for (Supplier<Type> type : TYPES) {
+      for (Supplier<Type> type : getTestTypes()) {
         Type testType = type.get(state);
         if (testType != null && state.getTypes().isSubtype(treeType, testType)) {
           matches.add(Signatures.prettyType(testType));
@@ -184,5 +144,52 @@ public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState
           ? Description.NO_MATCH
           : buildDescription(tree).setMessage(matches.toString()).build();
     }
+
+    /**
+     * Returns the type suppliers under test.
+     *
+     * @implNote The return value of this method should not be assigned to a field, as that would
+     *     prevent mutations introduced by Pitest from being killed.
+     */
+    private ImmutableSet<Supplier<Type>> getTestTypes() {
+      return ImmutableSet.of(
+          // Invalid types.
+          type("java.lang.Nonexistent"),
+          generic(type("java.util.Integer"), unbound()),
+          // Valid types.
+          type("java.lang.String"),
+          type("java.lang.Number"),
+          superOf(type("java.lang.Number")),
+          subOf(type("java.lang.Number")),
+          type("java.lang.Integer"),
+          superOf(type("java.lang.Integer")),
+          subOf(type("java.lang.Integer")),
+          type("java.util.Optional"),
+          raw(type("java.util.Optional")),
+          generic(type("java.util.Optional"), unbound()),
+          generic(type("java.util.Optional"), type("java.lang.Number")),
+          type("java.util.Collection"),
+          raw(type("java.util.Collection")),
+          generic(type("java.util.Collection"), unbound()),
+          generic(type("java.util.Collection"), type("java.lang.Number")),
+          generic(type("java.util.Collection"), superOf(type("java.lang.Number"))),
+          generic(type("java.util.Collection"), subOf(type("java.lang.Number"))),
+          generic(type("java.util.Collection"), type("java.lang.Integer")),
+          generic(type("java.util.Collection"), superOf(type("java.lang.Integer"))),
+          generic(type("java.util.Collection"), subOf(type("java.lang.Integer"))),
+          type("java.util.List"),
+          raw(type("java.util.List")),
+          generic(type("java.util.List"), unbound()),
+          generic(type("java.util.List"), type("java.lang.Number")),
+          generic(type("java.util.List"), superOf(type("java.lang.Number"))),
+          generic(type("java.util.List"), subOf(type("java.lang.Number"))),
+          generic(type("java.util.List"), type("java.lang.Integer")),
+          generic(type("java.util.List"), superOf(type("java.lang.Integer"))),
+          generic(type("java.util.List"), subOf(type("java.lang.Integer"))),
+          generic(
+              type("java.util.Map"),
+              type("java.lang.String"),
+              subOf(generic(type("java.util.Collection"), superOf(type("java.lang.Short"))))));
+    }
   }
 }
diff --git a/pom.xml b/pom.xml
@@ -1248,6 +1248,10 @@
                             <excludedClass>*.refaster*.*Rules*</excludedClass>
                         </excludedClasses>
                         <failWhenNoMutations>false</failWhenNoMutations>
+                        <mutators>
+                            <mutator>EXTENDED</mutator>
+                            <mutator>STRONGER</mutator>
+                        </mutators>
                         <!-- Use multiple threads to speed things up. Extend
                         timeouts to prevent false positives as a result of
                         contention. -->
@@ -1261,6 +1265,16 @@
                             <artifactId>pitest-git-plugin</artifactId>
                             <version>${version.pitest-git}</version>
                         </dependency>
+                        <dependency>
+                            <groupId>com.groupcdg.arcmutate</groupId>
+                            <artifactId>base</artifactId>
+                            <version>1.0.1</version>
+                        </dependency>
+                        <dependency>
+                            <groupId>com.groupcdg.pitest</groupId>
+                            <artifactId>pitest-accelerator-junit5</artifactId>
+                            <version>1.0.4</version>
+                        </dependency>
                         <dependency>
                             <groupId>org.pitest</groupId>
                             <artifactId>pitest-junit5-plugin</artifactId>