diff --git a/java/app_test.go b/java/app_test.go
index c189ee5..bb68132 100644
--- a/java/app_test.go
+++ b/java/app_test.go
@@ -2360,15 +2360,14 @@
 		}
 	`
 
-	config := testAppConfig(nil, bp, nil)
-	config.TestProductVariables.MissingUsesLibraries = []string{"baz"}
+	result := javaFixtureFactory.Extend(
+		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
+			variables.MissingUsesLibraries = []string{"baz"}
+		}),
+	).RunTestWithBp(t, bp)
 
-	ctx := testContext(config)
-
-	run(t, ctx, config)
-
-	app := ctx.ModuleForTests("app", "android_common")
-	prebuilt := ctx.ModuleForTests("prebuilt", "android_common")
+	app := result.ModuleForTests("app", "android_common")
+	prebuilt := result.ModuleForTests("prebuilt", "android_common")
 
 	// Test that implicit dependencies on java_sdk_library instances are passed to the manifest.
 	// This should not include explicit `uses_libs`/`optional_uses_libs` entries.
@@ -2380,10 +2379,7 @@
 		`--uses-library com.non.sdk.lib ` + // TODO(b/132357300): "com.non.sdk.lib" should not be passed to manifest_fixer
 		`--uses-library bar ` + // TODO(b/132357300): "bar" should not be passed to manifest_fixer
 		`--uses-library runtime-library`
-	if actualManifestFixerArgs != expectManifestFixerArgs {
-		t.Errorf("unexpected manifest_fixer args:\n\texpect: %q\n\tactual: %q",
-			expectManifestFixerArgs, actualManifestFixerArgs)
-	}
+	android.AssertStringEquals(t, "manifest_fixer args", expectManifestFixerArgs, actualManifestFixerArgs)
 
 	// Test that all libraries are verified (library order matters).
 	verifyCmd := app.Rule("verify_uses_libraries").RuleParams.Command
@@ -2394,9 +2390,7 @@
 		`--uses-library runtime-library ` +
 		`--optional-uses-library bar ` +
 		`--optional-uses-library baz `
-	if !strings.Contains(verifyCmd, verifyArgs) {
-		t.Errorf("wanted %q in %q", verifyArgs, verifyCmd)
-	}
+	android.AssertStringDoesContain(t, "verify cmd args", verifyCmd, verifyArgs)
 
 	// Test that all libraries are verified for an APK (library order matters).
 	verifyApkCmd := prebuilt.Rule("verify_uses_libraries").RuleParams.Command
@@ -2405,9 +2399,7 @@
 		`--uses-library android.test.runner ` +
 		`--optional-uses-library bar ` +
 		`--optional-uses-library baz `
-	if !strings.Contains(verifyApkCmd, verifyApkArgs) {
-		t.Errorf("wanted %q in %q", verifyApkArgs, verifyApkCmd)
-	}
+	android.AssertStringDoesContain(t, "verify apk cmd args", verifyApkCmd, verifyApkArgs)
 
 	// Test that all present libraries are preopted, including implicit SDK dependencies, possibly stubs
 	cmd := app.Rule("dexpreopt").RuleParams.Command
@@ -2418,46 +2410,39 @@
 		`PCL[/system/framework/non-sdk-lib.jar]#` +
 		`PCL[/system/framework/bar.jar]#` +
 		`PCL[/system/framework/runtime-library.jar]`
-	if !strings.Contains(cmd, w) {
-		t.Errorf("wanted %q in %q", w, cmd)
-	}
+	android.AssertStringDoesContain(t, "dexpreopt app cmd args", cmd, w)
 
 	// Test conditional context for target SDK version 28.
-	if w := `--target-context-for-sdk 28` +
-		` PCL[/system/framework/org.apache.http.legacy.jar] `; !strings.Contains(cmd, w) {
-		t.Errorf("wanted %q in %q", w, cmd)
-	}
+	android.AssertStringDoesContain(t, "dexpreopt app cmd 28", cmd,
+		`--target-context-for-sdk 28`+
+			` PCL[/system/framework/org.apache.http.legacy.jar] `)
 
 	// Test conditional context for target SDK version 29.
-	if w := `--target-context-for-sdk 29` +
-		` PCL[/system/framework/android.hidl.manager-V1.0-java.jar]` +
-		`#PCL[/system/framework/android.hidl.base-V1.0-java.jar] `; !strings.Contains(cmd, w) {
-		t.Errorf("wanted %q in %q", w, cmd)
-	}
+	android.AssertStringDoesContain(t, "dexpreopt app cmd 29", cmd,
+		`--target-context-for-sdk 29`+
+			` PCL[/system/framework/android.hidl.manager-V1.0-java.jar]`+
+			`#PCL[/system/framework/android.hidl.base-V1.0-java.jar] `)
 
 	// Test conditional context for target SDK version 30.
 	// "android.test.mock" is absent because "android.test.runner" is not used.
-	if w := `--target-context-for-sdk 30` +
-		` PCL[/system/framework/android.test.base.jar] `; !strings.Contains(cmd, w) {
-		t.Errorf("wanted %q in %q", w, cmd)
-	}
+	android.AssertStringDoesContain(t, "dexpreopt app cmd 30", cmd,
+		`--target-context-for-sdk 30`+
+			` PCL[/system/framework/android.test.base.jar] `)
 
 	cmd = prebuilt.Rule("dexpreopt").RuleParams.Command
-	if w := `--target-context-for-sdk any` +
-		` PCL[/system/framework/foo.jar]` +
-		`#PCL[/system/framework/non-sdk-lib.jar]` +
-		`#PCL[/system/framework/android.test.runner.jar]` +
-		`#PCL[/system/framework/bar.jar] `; !strings.Contains(cmd, w) {
-		t.Errorf("wanted %q in %q", w, cmd)
-	}
+	android.AssertStringDoesContain(t, "dexpreopt prebuilt cmd", cmd,
+		`--target-context-for-sdk any`+
+			` PCL[/system/framework/foo.jar]`+
+			`#PCL[/system/framework/non-sdk-lib.jar]`+
+			`#PCL[/system/framework/android.test.runner.jar]`+
+			`#PCL[/system/framework/bar.jar] `)
 
 	// Test conditional context for target SDK version 30.
 	// "android.test.mock" is present because "android.test.runner" is used.
-	if w := `--target-context-for-sdk 30` +
-		` PCL[/system/framework/android.test.base.jar]` +
-		`#PCL[/system/framework/android.test.mock.jar] `; !strings.Contains(cmd, w) {
-		t.Errorf("wanted %q in %q", w, cmd)
-	}
+	android.AssertStringDoesContain(t, "dexpreopt prebuilt cmd 30", cmd,
+		`--target-context-for-sdk 30`+
+			` PCL[/system/framework/android.test.base.jar]`+
+			`#PCL[/system/framework/android.test.mock.jar] `)
 }
 
 func TestCodelessApp(t *testing.T) {