Add a SkyFunction to perform toolchain resolution.

Part of #2219.

Change-Id: I339009c13639144ca756eb07c520df7d430a64e3
PiperOrigin-RevId: 161826487

src/test/java/com/google/devtools/build/lib/rules/platform/ToolchainTestCase.java

diff --git a/src/test/java/com/google/devtools/build/lib/rules/platform/ToolchainTestCase.java b/src/test/java/com/google/devtools/build/lib/rules/platform/ToolchainTestCase.java
index 87bce40..5d170ba 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/platform/ToolchainTestCase.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/platform/ToolchainTestCase.java
@@ -16,6 +16,7 @@
 
 import com.google.devtools.build.lib.analysis.platform.ConstraintSettingInfo;
 import com.google.devtools.build.lib.analysis.platform.ConstraintValueInfo;
+import com.google.devtools.build.lib.analysis.platform.PlatformInfo;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.skylark.util.SkylarkTestCase;
 import org.junit.Before;
@@ -23,11 +24,15 @@
 /** Utility methods for setting up platform and toolchain related tests. */
 public abstract class ToolchainTestCase extends SkylarkTestCase {
 
-  public Label testToolchainType;
+  public PlatformInfo targetPlatform;
+  public PlatformInfo hostPlatform;
+
   public ConstraintSettingInfo setting;
   public ConstraintValueInfo linuxConstraint;
   public ConstraintValueInfo macConstraint;
 
+  public Label testToolchainType;
+
   @Before
   public void createConstraints() throws Exception {
     scratch.file(
@@ -44,9 +49,15 @@
   }
 
   @Before
+  public void createPlatforms() throws Exception {
+    targetPlatform =
+        PlatformInfo.builder().setLabel(makeLabel("//platforms:target_platform")).build();
+    hostPlatform = PlatformInfo.builder().setLabel(makeLabel("//platforms:host_platform")).build();
+  }
+
+  @Before
   public void createToolchains() throws Exception {
-    rewriteWorkspace(
-        "register_toolchains(", "    '//toolchain:toolchain_1',", "    '//toolchain:toolchain_2')");
+    rewriteWorkspace("register_toolchains('//toolchain:toolchain_1',  '//toolchain:toolchain_2')");
 
     scratch.file(
         "toolchain/BUILD",

src/test/java/com/google/devtools/build/lib/skyframe/ToolchainResolutionFunctionTest.java

diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/ToolchainResolutionFunctionTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/ToolchainResolutionFunctionTest.java
new file mode 100644
index 0000000..88bc501
--- /dev/null
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/ToolchainResolutionFunctionTest.java
@@ -0,0 +1,85 @@
+// Copyright 2017 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.skyframe;
+
+import static com.google.common.truth.Truth.assertThat;
+import static com.google.devtools.build.skyframe.EvaluationResultSubjectFactory.assertThatEvaluationResult;
+
+import com.google.common.testing.EqualsTester;
+import com.google.devtools.build.lib.rules.platform.ToolchainTestCase;
+import com.google.devtools.build.lib.skyframe.util.SkyframeExecutorTestUtils;
+import com.google.devtools.build.skyframe.EvaluationResult;
+import com.google.devtools.build.skyframe.SkyKey;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/** Tests for {@link ToolchainResolutionValue} and {@link ToolchainResolutionFunction}. */
+@RunWith(JUnit4.class)
+public class ToolchainResolutionFunctionTest extends ToolchainTestCase {
+
+  private EvaluationResult<ToolchainResolutionValue> invokeToolchainResolution(SkyKey key)
+      throws InterruptedException {
+    try {
+      getSkyframeExecutor().getSkyframeBuildView().enableAnalysis(true);
+      return SkyframeExecutorTestUtils.evaluate(
+          getSkyframeExecutor(), key, /*keepGoing=*/ false, reporter);
+    } finally {
+      getSkyframeExecutor().getSkyframeBuildView().enableAnalysis(false);
+    }
+  }
+
+  // TODO(katre): Current toolchain resolution does not actually check the constraints, it just
+  // returns the first toolchain available.
+  @Test
+  public void testResolution() throws Exception {
+    SkyKey key =
+        ToolchainResolutionValue.key(targetConfig, testToolchainType, targetPlatform, hostPlatform);
+    EvaluationResult<ToolchainResolutionValue> result = invokeToolchainResolution(key);
+
+    assertThatEvaluationResult(result).hasNoError();
+
+    ToolchainResolutionValue toolchainResolutionValue = result.get(key);
+    assertThat(toolchainResolutionValue.toolchainLabel())
+        .isEqualTo(makeLabel("//toolchain:test_toolchain_1"));
+  }
+
+  @Test
+  public void testResolution_noneFound() throws Exception {
+    // Clear the toolchains.
+    rewriteWorkspace();
+
+    SkyKey key =
+        ToolchainResolutionValue.key(targetConfig, testToolchainType, targetPlatform, hostPlatform);
+    EvaluationResult<ToolchainResolutionValue> result = invokeToolchainResolution(key);
+
+    assertThatEvaluationResult(result)
+        .hasErrorEntryForKeyThat(key)
+        .hasExceptionThat()
+        .hasMessageThat()
+        .contains("no matching toolchain found for //toolchain:test_toolchain");
+  }
+
+  @Test
+  public void testToolchainResolutionValue_equalsAndHashCode() {
+    new EqualsTester()
+        .addEqualityGroup(
+            ToolchainResolutionValue.create(makeLabel("//test:toolchain_impl_1")),
+            ToolchainResolutionValue.create(makeLabel("//test:toolchain_impl_1")))
+        .addEqualityGroup(
+            ToolchainResolutionValue.create(makeLabel("//test:toolchain_impl_2")),
+            ToolchainResolutionValue.create(makeLabel("//test:toolchain_impl_2")));
+  }
+}