Add PrepareForTestWithBuildFlag

Add a helper function that creates a test fixture preparer that
sets a build flag, and use it everywhere that was setting build flags
manually.

Test: all soong tests
Flag: EXEMPT refactor
Change-Id: I68d50d68787a30d091f0827e8caa51f5c5a762ef
diff --git a/android/config_test.go b/android/config_test.go
index ca7c7f8..7732168 100644
--- a/android/config_test.go
+++ b/android/config_test.go
@@ -150,12 +150,7 @@
 
 	for _, tc := range testCases {
 		fixture := GroupFixturePreparers(
-			FixtureModifyProductVariables(func(vars FixtureProductVariables) {
-				if vars.BuildFlags == nil {
-					vars.BuildFlags = make(map[string]string)
-				}
-				vars.BuildFlags["RELEASE_ACONFIG_EXTRA_RELEASE_CONFIGS"] = tc.flag
-			}),
+			PrepareForTestWithBuildFlag("RELEASE_ACONFIG_EXTRA_RELEASE_CONFIGS", tc.flag),
 		)
 		actual := fixture.RunTest(t).Config.ReleaseAconfigExtraReleaseConfigs()
 		AssertArrayString(t, tc.name, tc.expected, actual)
diff --git a/android/prebuilt_test.go b/android/prebuilt_test.go
index 6e4fc0c..5e4af0b 100644
--- a/android/prebuilt_test.go
+++ b/android/prebuilt_test.go
@@ -574,11 +574,7 @@
 
 func TestPrebuiltErrorCannotListBothSourceAndPrebuiltInContributions(t *testing.T) {
 	selectMainlineModuleContritbutions := GroupFixturePreparers(
-		FixtureModifyProductVariables(func(variables FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "my_apex_contributions",
-			}
-		}),
+		PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "my_apex_contributions"),
 	)
 	testPrebuiltErrorWithFixture(t, `Found duplicate variations of the same module in apex_contributions: foo and prebuilt_foo. Please remove one of these`, `
 		source {
diff --git a/android/testing.go b/android/testing.go
index dae787b..e3853b8 100644
--- a/android/testing.go
+++ b/android/testing.go
@@ -174,6 +174,16 @@
 	config.TestAllowNonExistentPaths = false
 })
 
+// PrepareForTestWithBuildFlag returns a FixturePreparer that sets the given flag to the given value.
+func PrepareForTestWithBuildFlag(flag, value string) FixturePreparer {
+	return FixtureModifyProductVariables(func(variables FixtureProductVariables) {
+		if variables.BuildFlags == nil {
+			variables.BuildFlags = make(map[string]string)
+		}
+		variables.BuildFlags[flag] = value
+	})
+}
+
 func NewTestArchContext(config Config) *TestContext {
 	ctx := NewTestContext(config)
 	ctx.preDeps = append(ctx.preDeps, registerArchMutator)
diff --git a/apex/apex_test.go b/apex/apex_test.go
index 852f5fb..d6c8a8a 100644
--- a/apex/apex_test.go
+++ b/apex/apex_test.go
@@ -11299,11 +11299,7 @@
 				fs["platform/Test.java"] = nil
 			}),
 
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": tc.selectedApexContributions,
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", tc.selectedApexContributions),
 		)
 		ctx := testDexpreoptWithApexes(t, bp, "", preparer, fragment)
 		checkBootDexJarPath(t, ctx, "framework-foo", tc.expectedBootJar)
@@ -11442,11 +11438,7 @@
 			android.FixtureMergeMockFs(map[string][]byte{
 				"system/sepolicy/apex/com.android.foo-file_contexts": nil,
 			}),
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": tc.selectedApexContributions,
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", tc.selectedApexContributions),
 		)
 		if tc.expectedError != "" {
 			preparer = preparer.ExtendWithErrorHandler(android.FixtureExpectsOneErrorPattern(tc.expectedError))
@@ -11562,11 +11554,7 @@
 			android.FixtureMergeMockFs(map[string][]byte{
 				"system/sepolicy/apex/com.android.adservices-file_contexts": nil,
 			}),
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": tc.selectedApexContributions,
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", tc.selectedApexContributions),
 		)
 		ctx := testApex(t, bp, preparer)
 
diff --git a/apex/bootclasspath_fragment_test.go b/apex/bootclasspath_fragment_test.go
index 533f937..f8c823e 100644
--- a/apex/bootclasspath_fragment_test.go
+++ b/apex/bootclasspath_fragment_test.go
@@ -53,11 +53,7 @@
 		java.FixtureConfigureBootJars("com.android.art:baz", "com.android.art:quuz"),
 		java.FixtureConfigureApexBootJars("someapex:foo", "someapex:bar"),
 		prepareForTestWithArtApex,
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 		java.PrepareForTestWithJavaSdkLibraryFiles,
 		java.FixtureWithLastReleaseApis("foo", "baz"),
 	).RunTestWithBp(t, `
@@ -731,11 +727,7 @@
 
 		java.PrepareForTestWithJavaSdkLibraryFiles,
 		java.FixtureWithLastReleaseApis("foo", "quuz"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		apex {
 			name: "com.android.art",
diff --git a/apex/dexpreopt_bootjars_test.go b/apex/dexpreopt_bootjars_test.go
index 7a17f50..95db37d 100644
--- a/apex/dexpreopt_bootjars_test.go
+++ b/apex/dexpreopt_bootjars_test.go
@@ -399,11 +399,7 @@
 			java.FixtureConfigureBootJars("com.android.art:core-oj"),
 			PrepareForTestWithApexBuildComponents,
 			prepareForTestWithArtApex,
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ART": tc.selectedArtApexContributions,
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ART", tc.selectedArtApexContributions),
 		).RunTestWithBp(t, bp)
 
 		dexBootJars := result.ModuleForTests("dex_bootjars", "android_common")
diff --git a/apex/platform_bootclasspath_test.go b/apex/platform_bootclasspath_test.go
index 4a20cf0..645eebb 100644
--- a/apex/platform_bootclasspath_test.go
+++ b/apex/platform_bootclasspath_test.go
@@ -254,11 +254,7 @@
 		java.FixtureWithLastReleaseApis("foo"),
 		java.PrepareForTestWithDexpreopt,
 		dexpreopt.FixtureDisableDexpreoptBootImages(false),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		apex {
 			name: "com.android.art",
@@ -429,10 +425,9 @@
 		java.PrepareForTestWithJavaSdkLibraryFiles,
 		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
 			variables.Always_use_prebuilt_sdks = proptools.BoolPtr(true)
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
 		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
+
 		java.FixtureWithPrebuiltApis(map[string][]string{
 			"current": {},
 			"30":      {"foo"},
@@ -935,11 +930,7 @@
 			PrepareForTestWithApexBuildComponents,
 			prepareForTestWithMyapex,
 			java.FixtureConfigureApexBootJars(tc.configuredBootJars...),
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ART": "my_apex_contributions",
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ART", "my_apex_contributions"),
 		)
 		if tc.errorExpected {
 			fixture = fixture.ExtendWithErrorHandler(
diff --git a/cc/cc_test.go b/cc/cc_test.go
index b1c0945..7372fff 100644
--- a/cc/cc_test.go
+++ b/cc/cc_test.go
@@ -3194,12 +3194,7 @@
 
 	ctx = android.GroupFixturePreparers(
 		prepareForCcTest,
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			if variables.BuildFlags == nil {
-				variables.BuildFlags = make(map[string]string)
-			}
-			variables.BuildFlags["RELEASE_BOARD_API_LEVEL_FROZEN"] = "true"
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_BOARD_API_LEVEL_FROZEN", "true"),
 	).RunTestWithBp(t, bp)
 	testSdkVersionFlag("libfoo", "30")
 	testSdkVersionFlag("libbar", "29")
diff --git a/cc/prebuilt_test.go b/cc/prebuilt_test.go
index 86e6af9..acbbabc 100644
--- a/cc/prebuilt_test.go
+++ b/cc/prebuilt_test.go
@@ -476,11 +476,7 @@
 			android.FixtureRegisterWithContext(func(ctx android.RegistrationContext) {
 				android.RegisterApexContributionsBuildComponents(ctx)
 			}),
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "myapex_contributions",
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "myapex_contributions"),
 		)
 		ctx := testPrebuilt(t, fmt.Sprintf(bp, tc.selectedDependencyName), map[string][]byte{
 			"libbar.so": nil,
@@ -574,11 +570,7 @@
 			android.FixtureRegisterWithContext(func(ctx android.RegistrationContext) {
 				android.RegisterApexContributionsBuildComponents(ctx)
 			}),
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "myapex_contributions",
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "myapex_contributions"),
 		)
 		if tc.expectedErr != "" {
 			preparer = preparer.ExtendWithErrorHandler(android.FixtureExpectsAtLeastOneErrorMatchingPattern(tc.expectedErr))
@@ -638,11 +630,7 @@
 		android.FixtureRegisterWithContext(func(ctx android.RegistrationContext) {
 			android.RegisterApexContributionsBuildComponents(ctx)
 		}),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "myapex_contributions",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "myapex_contributions"),
 	)
 	ctx := testPrebuilt(t, bp, map[string][]byte{
 		"libbar.so": nil,
diff --git a/java/bootclasspath_fragment_test.go b/java/bootclasspath_fragment_test.go
index 8bc0a7e..d72417a 100644
--- a/java/bootclasspath_fragment_test.go
+++ b/java/bootclasspath_fragment_test.go
@@ -222,11 +222,7 @@
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("mysdklibrary", "myothersdklibrary", "mycoreplatform"),
 		FixtureConfigureApexBootJars("someapex:mysdklibrary"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		bootclasspath_fragment {
 			name: "myfragment",
diff --git a/java/droidstubs_test.go b/java/droidstubs_test.go
index 6a14f36..1e8362c 100644
--- a/java/droidstubs_test.go
+++ b/java/droidstubs_test.go
@@ -421,11 +421,9 @@
 	result := android.GroupFixturePreparers(
 		prepareForJavaTest,
 		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
 			variables.ExportRuntimeApis = proptools.BoolPtr(true)
 		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 		android.FixtureMergeMockFs(map[string][]byte{
 			"a/A.java":      nil,
 			"a/current.txt": nil,
diff --git a/java/hiddenapi_singleton_test.go b/java/hiddenapi_singleton_test.go
index 6229797..afe8b4c 100644
--- a/java/hiddenapi_singleton_test.go
+++ b/java/hiddenapi_singleton_test.go
@@ -203,10 +203,8 @@
 				FixtureConfigureBootJars("platform:foo"),
 				android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
 					variables.Always_use_prebuilt_sdks = proptools.BoolPtr(tc.unbundledBuild)
-					variables.BuildFlags = map[string]string{
-						"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-					}
 				}),
+				android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 			).RunTestWithBp(t, `
 		java_library {
 			name: "foo",
diff --git a/java/java_test.go b/java/java_test.go
index 2d4fca2..86bfe9f 100644
--- a/java/java_test.go
+++ b/java/java_test.go
@@ -2634,11 +2634,7 @@
 	for _, tc := range testCases {
 		ctx := android.GroupFixturePreparers(
 			prepareForJavaTest,
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "myapex_contributions",
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "myapex_contributions"),
 		).RunTestWithBp(t, fmt.Sprintf(bp, tc.selectedDependencyName))
 
 		// check that rdep gets the correct variation of dep
@@ -2708,11 +2704,7 @@
 		ctx := android.GroupFixturePreparers(
 			prepareForJavaTest,
 			PrepareForTestWithPlatformCompatConfig,
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "myapex_contributions",
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "myapex_contributions"),
 		).RunTestWithBp(t, fmt.Sprintf(bp, tc.selectedDependencyName))
 
 		mergedGlobalConfig := ctx.SingletonForTests("platform_compat_config_singleton").Output("compat_config/merged_compat_config.xml")
diff --git a/java/sdk_library_test.go b/java/sdk_library_test.go
index 911e8b1..368eca7 100644
--- a/java/sdk_library_test.go
+++ b/java/sdk_library_test.go
@@ -35,11 +35,7 @@
 			"29": {"foo"},
 			"30": {"bar", "barney", "baz", "betty", "foo", "fred", "quuz", "wilma"},
 		}),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		droiddoc_exported_dir {
 			name: "droiddoc-templates-sdk",
@@ -537,11 +533,7 @@
 		prepareForJavaTest,
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("sdklib"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		java_sdk_library {
 			name: "sdklib",
@@ -934,11 +926,7 @@
 		prepareForJavaTest,
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("sdklib"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		java_sdk_library {
 			name: "sdklib",
@@ -987,11 +975,7 @@
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("sdklib"),
 		preparer,
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		java_sdk_library {
 			name: "sdklib",
@@ -1183,11 +1167,7 @@
 		prepareForJavaTest,
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("sdklib.source_preferred_using_legacy_flags", "sdklib.prebuilt_preferred_using_legacy_flags"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "my_mainline_module_contributions",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "my_mainline_module_contributions"),
 	).RunTestWithBp(t, bp)
 
 	// Make sure that rdeps get the correct source vs prebuilt based on mainline_module_contributions
@@ -1369,11 +1349,7 @@
 			"sdklib_group_foo",
 			"sdklib_owner_foo",
 			"foo"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		java_sdk_library {
 			name: "sdklib_no_group",
@@ -1785,12 +1761,8 @@
 		prepareForJavaTest,
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("sdklib"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				// We can use any of the apex contribution build flags from build/soong/android/config.go#mainlineApexContributionBuildFlags here
-				"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "my_mainline_module_contributions",
-			}
-		}),
+		// We can use any of the apex contribution build flags from build/soong/android/config.go#mainlineApexContributionBuildFlags here
+		android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "my_mainline_module_contributions"),
 	)
 
 	result := fixture.RunTestWithBp(t, bp)
@@ -1873,11 +1845,7 @@
 		prepareForJavaTest,
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("sdklib", "sdklib.v1", "sdklib.v2"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "my_mainline_module_contributions",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "my_mainline_module_contributions"),
 	)
 
 	for _, tc := range testCases {
diff --git a/java/system_modules_test.go b/java/system_modules_test.go
index 336dd21..1a8d0b5 100644
--- a/java/system_modules_test.go
+++ b/java/system_modules_test.go
@@ -182,11 +182,7 @@
 	for _, tc := range testCases {
 		res := android.GroupFixturePreparers(
 			prepareForJavaTest,
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "myapex_contributions",
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "myapex_contributions"),
 		).RunTestWithBp(t, fmt.Sprintf(bp, tc.selectedDependencyName))
 
 		// check that rdep gets the correct variation of system_modules
diff --git a/sdk/bootclasspath_fragment_sdk_test.go b/sdk/bootclasspath_fragment_sdk_test.go
index 7048a15..7ee548f 100644
--- a/sdk/bootclasspath_fragment_sdk_test.go
+++ b/sdk/bootclasspath_fragment_sdk_test.go
@@ -276,11 +276,7 @@
 		// Add a platform_bootclasspath that depends on the fragment.
 		fixtureAddPlatformBootclasspathForBootclasspathFragment("myapex", "mybootclasspathfragment"),
 
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 		// Make sure that we have atleast one platform library so that we can check the monolithic hiddenapi
 		// file creation.
 		java.FixtureConfigureBootJars("platform:foo"),
@@ -799,11 +795,7 @@
 		// Add a platform_bootclasspath that depends on the fragment.
 		fixtureAddPlatformBootclasspathForBootclasspathFragment("myapex", "mybootclasspathfragment"),
 
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 
 		android.MockFS{
 			"my-blocked.txt":                   nil,
@@ -1053,11 +1045,7 @@
 			variables.Platform_version_active_codenames = []string{"VanillaIceCream"}
 		}),
 
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 
 		android.FixtureWithRootAndroidBp(`
 			sdk {
diff --git a/sdk/java_sdk_test.go b/sdk/java_sdk_test.go
index 0a5483b..0fb5c70 100644
--- a/sdk/java_sdk_test.go
+++ b/sdk/java_sdk_test.go
@@ -45,11 +45,7 @@
 	java.PrepareForTestWithJavaDefaultModules,
 	java.PrepareForTestWithJavaSdkLibraryFiles,
 	java.FixtureWithLastReleaseApis("myjavalib"),
-	android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-		variables.BuildFlags = map[string]string{
-			"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-		}
-	}),
+	android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 )
 
 // Contains tests for SDK members provided by the java package.
@@ -666,11 +662,7 @@
 			"1": {"myjavalib"},
 			"2": {"myjavalib"},
 		}),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		sdk {
 			name: "mysdk",
@@ -1313,11 +1305,7 @@
 func TestSnapshotWithJavaSdkLibrary_CompileDex(t *testing.T) {
 	result := android.GroupFixturePreparers(
 		prepareForSdkTestWithJavaSdkLibrary,
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		sdk {
 			name: "mysdk",
diff --git a/sdk/sdk_test.go b/sdk/sdk_test.go
index 4894210..057b370 100644
--- a/sdk/sdk_test.go
+++ b/sdk/sdk_test.go
@@ -457,11 +457,7 @@
 			android.FixtureMergeEnv(map[string]string{
 				"SOONG_SDK_SNAPSHOT_TARGET_BUILD_RELEASE": "S",
 			}),
-			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-				}
-			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 		).RunTest(t)
 
 		CheckSnapshot(t, result, "mysdk", "",
@@ -573,11 +569,9 @@
 				"SOONG_SDK_SNAPSHOT_TARGET_BUILD_RELEASE": "S",
 			}),
 			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-				variables.BuildFlags = map[string]string{
-					"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-				}
 				variables.Platform_version_active_codenames = []string{"UpsideDownCake", "Tiramisu", "S-V2"}
 			}),
+			android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 		).RunTest(t)
 
 		CheckSnapshot(t, result, "mysdk", "",