diff --git a/tests/utils/testutils/Android.bp b/tests/utils/testutils/Android.bp
index 0a9e964d8d8db..f71be7b0b7d3e 100644
--- a/tests/utils/testutils/Android.bp
+++ b/tests/utils/testutils/Android.bp
@@ -19,7 +19,10 @@ java_library {
 
     srcs: ["java/**/*.java"],
 
-    static_libs: ["junit"],
+    static_libs: [
+        "junit",
+        "hamcrest-library",
+    ],
 
     libs: [
         "android.test.runner",
diff --git a/core/tests/coretests/src/com/android/server/wm/test/filters/CoreTestsFilter.java b/tests/utils/testutils/java/com/android/server/wm/test/filters/CoreTestsFilter.java
similarity index 100%
rename from core/tests/coretests/src/com/android/server/wm/test/filters/CoreTestsFilter.java
rename to tests/utils/testutils/java/com/android/server/wm/test/filters/CoreTestsFilter.java
diff --git a/tests/utils/testutils/java/com/android/test/filters/SelectTest.java b/tests/utils/testutils/java/com/android/test/filters/SelectTest.java
index d0350aff5ef56..d5b14c58512ea 100644
--- a/tests/utils/testutils/java/com/android/test/filters/SelectTest.java
+++ b/tests/utils/testutils/java/com/android/test/filters/SelectTest.java
@@ -26,10 +26,12 @@ import com.android.internal.annotations.VisibleForTesting;
 import org.junit.runner.Description;
 import org.junit.runner.manipulation.Filter;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.StringJoiner;
@@ -131,7 +133,8 @@ public class SelectTest extends Filter {
      *
      * @param testArgs instrumentation test arguments.
      * @param selectTests array of class name to be selected to run.
-     * @return modified instrumentation test arguments.
+     * @return modified instrumentation test arguments. if {@link #OPTION_SELECT_TEST} argument
+     *      already exists in {@code testArgs}, those are prepended before {@code selectTests}.
      */
     @NonNull
     protected static Bundle addSelectTest(
@@ -139,7 +142,13 @@ public class SelectTest extends Filter {
         if (selectTests.length == 0) {
             return testArgs;
         }
-        testArgs.putString(OPTION_SELECT_TEST, join(Arrays.asList(selectTests)));
+        final List<String> selectedTestList = new ArrayList<>();
+        final String selectTestArgs = testArgs.getString(OPTION_SELECT_TEST);
+        if (selectTestArgs != null) {
+            selectedTestList.addAll(Arrays.asList(selectTestArgs.split(ARGUMENT_ITEM_SEPARATOR)));
+        }
+        selectedTestList.addAll(Arrays.asList(selectTests));
+        testArgs.putString(OPTION_SELECT_TEST, join(selectedTestList));
         return testArgs;
     }
 
diff --git a/tests/utils/testutils/java/com/android/test/filters/SelectTestTests.java b/tests/utils/testutils/java/com/android/test/filters/SelectTestTests.java
index 163b00abafcd0..df18985f77bf3 100644
--- a/tests/utils/testutils/java/com/android/test/filters/SelectTestTests.java
+++ b/tests/utils/testutils/java/com/android/test/filters/SelectTestTests.java
@@ -19,7 +19,11 @@ package com.android.test.filters;
 import static com.android.test.filters.SelectTest.OPTION_SELECT_TEST;
 import static com.android.test.filters.SelectTest.OPTION_SELECT_TEST_VERBOSE;
 
+import static org.hamcrest.collection.IsArrayContaining.hasItemInArray;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
 
 import android.os.Bundle;
@@ -145,6 +149,45 @@ public class SelectTestTests {
         }
     }
 
+    @Test
+    public void testAddSelectTest() {
+        final Bundle testArgs = new Bundle();
+
+        final Bundle modifiedTestArgs =
+                SelectTest.addSelectTest(testArgs, PACKAGE_A, CLASS_B3, METHOD_C5X);
+        assertSame(testArgs, modifiedTestArgs);
+
+        final String selectTestArgs = modifiedTestArgs.getString(OPTION_SELECT_TEST);
+        assertNotNull(selectTestArgs);
+        final String[] selectedTests = selectTestArgs.split(",");
+        assertThat(selectedTests, hasItemInArray(PACKAGE_A));
+        assertThat(selectedTests, hasItemInArray(CLASS_B3));
+        assertThat(selectedTests, hasItemInArray(METHOD_C5X));
+    }
+
+    @Test
+    public void testAddSelectTest_prependExistingTestArg() {
+        final Bundle testArgs = new Bundle();
+        testArgs.putString(OPTION_SELECT_TEST, new StringJoiner(",")
+                .add(PACKAGE_A)
+                .add(CLASS_B3)
+                .add(METHOD_C5X)
+                .toString());
+
+        final Bundle modifiedTestArgs =
+                SelectTest.addSelectTest(testArgs, PACKAGE_B, CLASS_B4, METHOD_C6Y);
+
+        final String selectTestArgs = modifiedTestArgs.getString(OPTION_SELECT_TEST);
+        assertNotNull(selectTestArgs);
+        final String[] selectedTests = selectTestArgs.split(",");
+        assertThat(selectedTests, hasItemInArray(PACKAGE_A));
+        assertThat(selectedTests, hasItemInArray(CLASS_B3));
+        assertThat(selectedTests, hasItemInArray(METHOD_C5X));
+        assertThat(selectedTests, hasItemInArray(PACKAGE_B));
+        assertThat(selectedTests, hasItemInArray(CLASS_B4));
+        assertThat(selectedTests, hasItemInArray(METHOD_C6Y));
+    }
+
     @Test
     public void testFilterDisabled() {
         final Filter filter = mBuilder.build();