Introduce an Extrema aggregator.

RELNOTES: None
PiperOrigin-RevId: 187370833

2 files changed, 86 insertions, 1 deletions

diff --git a/src/test/java/com/google/devtools/build/lib/collect/ExtremaTest.java b/src/test/java/com/google/devtools/build/lib/collect/ExtremaTest.java
new file mode 100644
index 0000000000..1f86a042fe
--- /dev/null
+++ b/src/test/java/com/google/devtools/build/lib/collect/ExtremaTest.java
@@ -0,0 +1,84 @@
+// Copyright 2018 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.google.devtools.build.lib.collect;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.common.collect.ImmutableList;
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/** Tests for {@link Extrema}. */
+@RunWith(JUnit4.class)
+public class ExtremaTest {
+  @Test
+  public void handlesDupes() {
+    Extrema<Integer> extrema = Extrema.min(3);
+    extrema.aggregate(4);
+    extrema.aggregate(3);
+    extrema.aggregate(1);
+    extrema.aggregate(2);
+    extrema.aggregate(1);
+    extrema.aggregate(3);
+    extrema.aggregate(1);
+    assertThat(extrema.getExtremeElements()).containsExactly(1, 1, 1);
+  }
+
+  @Test
+  public void minExtremaSmallK() {
+    runRangeTest(Extrema.min(5), 1, 100, ImmutableList.of(1, 2, 3, 4, 5));
+  }
+
+  @Test
+  public void minExtremaLargeK() {
+    runRangeTest(Extrema.min(10), 1, 5, ImmutableList.of(1, 2, 3, 4, 5));
+  }
+
+  @Test
+  public void maxExtremaSmallK() {
+    runRangeTest(Extrema.max(5), 1, 100, ImmutableList.of(100, 99, 98, 97, 96));
+  }
+
+  @Test
+  public void maxExtremaLargeK() {
+    runRangeTest(Extrema.max(10), 1, 5, ImmutableList.of(5, 4, 3, 2, 1));
+  }
+
+  private void runRangeTest(
+      Extrema<Integer> extrema,
+      int leftEndpointInclusive,
+      int rightEndpointInclusive,
+      ImmutableList<Integer> expected) {
+    assertThat(extrema.getExtremeElements()).isEmpty();
+    closedRangeShuffled(leftEndpointInclusive, rightEndpointInclusive).forEach(extrema::aggregate);
+    assertThat(extrema.getExtremeElements()).containsExactlyElementsIn(expected).inOrder();
+    extrema.clear();
+    assertThat(extrema.getExtremeElements()).isEmpty();
+  }
+
+  private static Stream<Integer> closedRangeShuffled(
+      int leftEndpointInclusive, int rightEndpointInclusive) {
+    List<Integer> list =
+        IntStream.rangeClosed(leftEndpointInclusive, rightEndpointInclusive).boxed().collect(
+            Collectors.toList());
+    Collections.shuffle(list);
+    return list.stream();
+  }
+}
diff --git a/src/test/java/com/google/devtools/build/lib/testutil/BazelPackageBuilderHelperForTesting.java b/src/test/java/com/google/devtools/build/lib/testutil/BazelPackageBuilderHelperForTesting.java
index b5522a0007..2bd6cf6d8e 100644
--- a/src/test/java/com/google/devtools/build/lib/testutil/BazelPackageBuilderHelperForTesting.java
+++ b/src/test/java/com/google/devtools/build/lib/testutil/BazelPackageBuilderHelperForTesting.java
@@ -47,7 +47,8 @@ public class BazelPackageBuilderHelperForTesting implements Package.Builder.Help
   }
 
   @Override
-  public void onLoadingComplete(Package pkg, SkylarkSemantics skylarkSemantics) {
+  public void onLoadingComplete(
+      Package pkg, SkylarkSemantics skylarkSemantics, long loadTimeNanos) {
     sanityCheckBazelPackageLoader(pkg, ruleClassProvider, skylarkSemantics);
   }