Add tests for FrameMetricsCalculator

Author: jeremyjiang-dev

firebase-perf/src/main/java/com/google/firebase/perf/metrics/FrameMetricsCalculator.java

@@ -1,6 +1,8 @@
 package com.google.firebase.perf.metrics;
 
 import android.util.SparseIntArray;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.core.app.FrameMetricsAggregator;
 import com.google.firebase.perf.util.Constants;
 
@@ -35,7 +37,7 @@ public int getTotalFrames() {
    * @param arr the metrics data collected by {@link FrameMetricsAggregator}
    * @return the frame metrics
    */
-  public static FrameMetrics calculateFrameMetrics(SparseIntArray[] arr) {
+  public static @NonNull FrameMetrics calculateFrameMetrics(@Nullable SparseIntArray[] arr) {
     int totalFrames = 0;
     int slowFrames = 0;
     int frozenFrames = 0;

firebase-perf/src/test/java/com/google/firebase/perf/metrics/FrameMetricsCalculatorTest.java

@@ -0,0 +1,74 @@
+package com.google.firebase.perf.metrics;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.util.SparseIntArray;
+
+import androidx.core.app.FrameMetricsAggregator;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+/** Unit tests for {@link FrameMetricsCalculator}. */
+@RunWith(RobolectricTestRunner.class)
+public class FrameMetricsCalculatorTest {
+  @Test
+  public void calculateFrameMetrics_inputIsNull_returnsFrameMetricsWithAllZeros() {
+    SparseIntArray[] arr = new SparseIntArray[1];
+    arr[FrameMetricsAggregator.TOTAL_INDEX] = null;
+    FrameMetricsCalculator.FrameMetrics metrics = FrameMetricsCalculator.calculateFrameMetrics(arr);
+    assertThat(metrics.getTotalFrames()).isEqualTo(0);
+    assertThat(metrics.getSlowFrames()).isEqualTo(0);
+    assertThat(metrics.getFrozenFrames()).isEqualTo(0);
+  }
+
+  @Test
+  public void calculateFrameMetrics_validSparseIntArray_returnsCorrectFrameMetrics() {
+    // For a given non-null SparseIntArray, the results stored are the number of samples at each millisecond value (rounded).
+    // Slow frames are duration greater than 16ms and frozen frames are duration greater than 700ms.
+    SparseIntArray sparseIntArray = new SparseIntArray();
+    sparseIntArray.append(5, 3);
+    sparseIntArray.append(20, 2);
+    sparseIntArray.append(800, 5);
+    SparseIntArray[] arr = new SparseIntArray[1];
+    arr[FrameMetricsAggregator.TOTAL_INDEX] = sparseIntArray;
+
+    FrameMetricsCalculator.FrameMetrics metrics = FrameMetricsCalculator.calculateFrameMetrics(arr);
+    assertThat(metrics.getTotalFrames()).isEqualTo(10);
+    assertThat(metrics.getSlowFrames()).isEqualTo(7);
+    assertThat(metrics.getFrozenFrames()).isEqualTo(5);
+  }
+
+  @Test
+  public void calculateFrameMetrics_validSparseIntArrayWithoutFrozenFrames_returnsCorrectFrameMetrics() {
+    // For a given non-null SparseIntArray, the results stored are the number of samples at each millisecond value (rounded).
+    // Slow frames are duration greater than 16ms and frozen frames are duration greater than 700ms.
+    SparseIntArray sparseIntArray = new SparseIntArray();
+    sparseIntArray.append(5, 3);
+    sparseIntArray.append(20, 2);
+    SparseIntArray[] arr = new SparseIntArray[1];
+    arr[FrameMetricsAggregator.TOTAL_INDEX] = sparseIntArray;
+
+    FrameMetricsCalculator.FrameMetrics metrics = FrameMetricsCalculator.calculateFrameMetrics(arr);
+    assertThat(metrics.getTotalFrames()).isEqualTo(5);
+    assertThat(metrics.getSlowFrames()).isEqualTo(2);
+    assertThat(metrics.getFrozenFrames()).isEqualTo(0);
+  }
+
+  @Test
+  public void calculateFrameMetrics_validSparseIntArrayWithoutSlowFrames_returnsCorrectFrameMetrics() {
+    // For a given non-null SparseIntArray, the results stored are the number of samples at each millisecond value (rounded).
+    // Slow frames are duration greater than 16ms and frozen frames are duration greater than 700ms.
+    SparseIntArray sparseIntArray = new SparseIntArray();
+    sparseIntArray.append(5, 3);
+    sparseIntArray.append(701, 2);
+    SparseIntArray[] arr = new SparseIntArray[1];
+    arr[FrameMetricsAggregator.TOTAL_INDEX] = sparseIntArray;
+
+    FrameMetricsCalculator.FrameMetrics metrics = FrameMetricsCalculator.calculateFrameMetrics(arr);
+    assertThat(metrics.getTotalFrames()).isEqualTo(5);
+    assertThat(metrics.getSlowFrames()).isEqualTo(2);
+    assertThat(metrics.getFrozenFrames()).isEqualTo(2);
+  }
+}