diff --git a/android/mutator.go b/android/mutator.go
index a06e0ee46..e25e2e8f1 100644
--- a/android/mutator.go
+++ b/android/mutator.go
@@ -202,7 +202,7 @@ var postDeps = []RegisterMutatorFunc{
 	RegisterPrebuiltsPostDepsMutators,
 	RegisterVisibilityRuleEnforcer,
 	RegisterLicensesDependencyChecker,
-	RegisterNeverallowMutator,
+	registerNeverallowMutator,
 	RegisterOverridePostDepsMutators,
 }
 
diff --git a/android/neverallow.go b/android/neverallow.go
index 7455e6a78..a385bbc0c 100644
--- a/android/neverallow.go
+++ b/android/neverallow.go
@@ -42,7 +42,7 @@ import (
 //     counts as a match
 // - it has none of the "Without" properties matched (same rules as above)
 
-func RegisterNeverallowMutator(ctx RegisterMutatorsContext) {
+func registerNeverallowMutator(ctx RegisterMutatorsContext) {
 	ctx.BottomUp("neverallow", neverallowMutator).Parallel()
 }
 
@@ -661,6 +661,22 @@ func neverallowRules(config Config) []Rule {
 // Overrides the default neverallow rules for the supplied config.
 //
 // For testing only.
-func SetTestNeverallowRules(config Config, testRules []Rule) {
+func setTestNeverallowRules(config Config, testRules []Rule) {
 	config.Once(neverallowRulesKey, func() interface{} { return testRules })
 }
+
+// Prepares for a test by setting neverallow rules and enabling the mutator.
+//
+// If the supplied rules are nil then the default rules are used.
+func PrepareForTestWithNeverallowRules(testRules []Rule) FixturePreparer {
+	return GroupFixturePreparers(
+		FixtureModifyConfig(func(config Config) {
+			if testRules != nil {
+				setTestNeverallowRules(config, testRules)
+			}
+		}),
+		FixtureRegisterWithContext(func(ctx RegistrationContext) {
+			ctx.PostDepsMutators(registerNeverallowMutator)
+		}),
+	)
+}
diff --git a/android/neverallow_test.go b/android/neverallow_test.go
index de0197a80..268346a7b 100644
--- a/android/neverallow_test.go
+++ b/android/neverallow_test.go
@@ -292,7 +292,6 @@ var prepareForNeverAllowTest = GroupFixturePreparers(
 		ctx.RegisterModuleType("java_library_host", newMockJavaLibraryModule)
 		ctx.RegisterModuleType("java_device_for_host", newMockJavaLibraryModule)
 		ctx.RegisterModuleType("makefile_goal", newMockMakefileGoalModule)
-		ctx.PostDepsMutators(RegisterNeverallowMutator)
 	}),
 )
 
@@ -301,12 +300,7 @@ func TestNeverallow(t *testing.T) {
 		t.Run(test.name, func(t *testing.T) {
 			GroupFixturePreparers(
 				prepareForNeverAllowTest,
-				FixtureModifyConfig(func(config Config) {
-					// If the test has its own rules then use them instead of the default ones.
-					if test.rules != nil {
-						SetTestNeverallowRules(config, test.rules)
-					}
-				}),
+				PrepareForTestWithNeverallowRules(test.rules),
 				test.fs.AddToFixture(),
 			).
 				ExtendWithErrorHandler(FixtureExpectsAllErrorsToMatchAPattern(test.expectedErrors)).
diff --git a/apex/apex_test.go b/apex/apex_test.go
index 407faa1a8..d2baf1bb6 100644
--- a/apex/apex_test.go
+++ b/apex/apex_test.go
@@ -6658,45 +6658,33 @@ func testApexPermittedPackagesRules(t *testing.T, errmsg, bp string, apexBootJar
 		public_key: "testkey.avbpubkey",
 		private_key: "testkey.pem",
 	}`
-	fs := map[string][]byte{
+	fs := android.MockFS{
 		"lib1/src/A.java": nil,
 		"lib2/src/B.java": nil,
 		"system/sepolicy/apex/myapex-file_contexts": nil,
 	}
 
-	config := android.TestArchConfig(t.TempDir(), nil, bp, fs)
-	android.SetTestNeverallowRules(config, rules)
-	updatableBootJars := make([]string, 0, len(apexBootJars))
-	for _, apexBootJar := range apexBootJars {
-		updatableBootJars = append(updatableBootJars, "myapex:"+apexBootJar)
+	errorHandler := android.FixtureExpectsNoErrors
+	if errmsg != "" {
+		errorHandler = android.FixtureExpectsAtLeastOneErrorMatchingPattern(errmsg)
 	}
-	config.TestProductVariables.UpdatableBootJars = android.CreateTestConfiguredJarList(updatableBootJars)
 
-	ctx := android.NewTestArchContext(config)
-	ctx.RegisterModuleType("apex", BundleFactory)
-	ctx.RegisterModuleType("apex_key", ApexKeyFactory)
-	ctx.PreArchMutators(android.RegisterDefaultsPreArchMutators)
-	cc.RegisterRequiredBuildComponentsForTest(ctx)
-	java.RegisterRequiredBuildComponentsForTest(ctx)
-	ctx.PostDepsMutators(android.RegisterOverridePostDepsMutators)
-	ctx.PreDepsMutators(RegisterPreDepsMutators)
-	ctx.PostDepsMutators(RegisterPostDepsMutators)
-	ctx.PostDepsMutators(android.RegisterNeverallowMutator)
-
-	ctx.Register()
-
-	_, errs := ctx.ParseBlueprintsFiles("Android.bp")
-	android.FailIfErrored(t, errs)
-
-	_, errs = ctx.PrepareBuildActions(config)
-	if errmsg == "" {
-		android.FailIfErrored(t, errs)
-	} else if len(errs) > 0 {
-		android.FailIfNoMatchingErrors(t, errmsg, errs)
-		return
-	} else {
-		t.Fatalf("missing expected error %q (0 errors are returned)", errmsg)
-	}
+	android.GroupFixturePreparers(
+		android.PrepareForTestWithAndroidBuildComponents,
+		java.PrepareForTestWithJavaBuildComponents,
+		PrepareForTestWithApexBuildComponents,
+		android.PrepareForTestWithNeverallowRules(rules),
+		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
+			updatableBootJars := make([]string, 0, len(apexBootJars))
+			for _, apexBootJar := range apexBootJars {
+				updatableBootJars = append(updatableBootJars, "myapex:"+apexBootJar)
+			}
+			variables.UpdatableBootJars = android.CreateTestConfiguredJarList(updatableBootJars)
+		}),
+		fs.AddToFixture(),
+	).
+		ExtendWithErrorHandler(errorHandler).
+		RunTestWithBp(t, bp)
 }
 
 func TestApexPermittedPackagesRules(t *testing.T) {