Move ShardingFilter to androidx.test.filters.

runner/android_junit_runner/java/androidx/test/filters/ShardingFilter.java

@@ -0,0 +1,40 @@
+package androidx.test.filters;
+
+import androidx.annotation.RestrictTo;
+import androidx.annotation.RestrictTo.Scope;
+import org.junit.runner.Description;
+import org.junit.runner.manipulation.Filter;
+
+/**
+ * A JUnit sharding filter uses the hashcode of the test description to assign it to a shard.
+ *
+ * @hide
+ */
+@RestrictTo(Scope.LIBRARY)
+public class ShardingFilter extends Filter {
+  private final int numShards;
+  private final int shardIndex;
+
+  public ShardingFilter(int numShards, int shardIndex) {
+    this.numShards = numShards;
+    this.shardIndex = shardIndex;
+  }
+
+  @Override
+  public boolean shouldRun(Description description) {
+    if (description.isTest()) {
+      return (Math.floorMod(description.hashCode(), numShards)) == shardIndex;
+    }
+
+    // The description is a suite, so assume that it can be run so that filtering is
+    // applied to its children. If after filtering it has no children then it will be
+    // automatically filtered out.
+    return true;
+  }
+
+  /** {@inheritDoc} */
+  @Override
+  public String describe() {
+    return String.format("Shard %d of %d shards", shardIndex, numShards);
+  }
+}

runner/android_junit_runner/java/androidx/test/internal/runner/TestRequestBuilder.java

@@ -25,6 +25,7 @@
 import androidx.test.filters.CustomFilter;
 import androidx.test.filters.RequiresDevice;
 import androidx.test.filters.SdkSuppressFilter;
+import androidx.test.filters.ShardingFilter;
 import androidx.test.filters.TestsRegExFilter;
 import androidx.test.internal.runner.ClassPathScanner.ChainedClassNameFilter;
 import androidx.test.internal.runner.ClassPathScanner.ExcludeClassNamesFilter;
@@ -277,34 +278,6 @@ public String describe() {
     }
   }
 
-  private static class ShardingFilter extends Filter {
-    private final int numShards;
-    private final int shardIndex;
-
-    ShardingFilter(int numShards, int shardIndex) {
-      this.numShards = numShards;
-      this.shardIndex = shardIndex;
-    }
-
-    @Override
-    public boolean shouldRun(Description description) {
-      if (description.isTest()) {
-        return (Math.abs(description.hashCode()) % numShards) == shardIndex;
-      }
-
-      // The description is a suite, so assume that it can be run so that filtering is
-      // applied to its children. If after filtering it has no children then it will be
-      // automatically filtered out.
-      return true;
-    }
-
-    /** {@inheritDoc} */
-    @Override
-    public String describe() {
-      return String.format("Shard %s of %s shards", shardIndex, numShards);
-    }
-  }
-
   /**
    * A {@link Request} that doesn't report an error if all tests are filtered out. Done for
    * consistency with InstrumentationTestRunner.