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// Copyright 2015 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.analysis.util;
import static com.google.common.truth.Truth.assertThat;
import static com.google.common.truth.Truth.assertWithMessage;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;
import com.google.devtools.build.lib.actions.Action;
import com.google.devtools.build.lib.actions.ActionKeyContext;
import com.google.devtools.build.lib.actions.Actions;
import java.util.ArrayList;
import java.util.BitSet;
import java.util.EnumSet;
import java.util.List;
import javax.annotation.CheckReturnValue;
/**
* Test helper for testing {@link Action} implementations.
*/
public class ActionTester {
/** A generator for action instances. */
public interface ActionCombinationFactory<E extends Enum<E>> {
/**
* Returns a new action instance. The parameter {@code attributesToFlip} is used to vary the
* parameters used to create the action. Implementations should do something like this: <code>
* <pre>
* private enum KeyAttributes { ATTR_1, ATTR_2, ATTR_3, ATTR_4 }
* return new MyAction(owner, inputs, outputs, configuration,
* attributesToFlip.contains(ATTR_0) ? a1 : a2,
* attributesToFlip.contains(ATTR_1) ? b1 : b2,
* attributesToFlip.contains(ATTR_2) ? c1 : c2,
* attributesToFlip.contains(ATTR_3) ? d1 : d2);
* </pre>
* </code>
*
* <p>To reduce the combinatorial complexity of testing an action class, all elements that are
* only used to change the executed command line should go into a single parameter, and the key
* computation should take the generated command line into account.
*
* <p>Furthermore, when called with identical parameters, this method should return different
* instances (i.e. according to {@code ==}), but they should have the same key.
*
* @param attributesToFlip
*/
Action generate(ImmutableSet<E> attributesToFlip) throws Exception;
}
private final ActionKeyContext actionKeyContext;
private final List<Action> actions = new ArrayList<>();
public ActionTester(ActionKeyContext actionKeyContext) {
this.actionKeyContext = actionKeyContext;
}
public ActionTester() {
this(new ActionKeyContext());
}
/**
* Creates all possible combinations of actions given a set of flags which can be either on or
* off. This requires that all combinations result in different actions, i.e., all flags must be
* orthogonal. The generated actions are added to a local list for a subsequent call to {@link
* #runTest}. This method can be called multiple times to generate different sets of actions.
*/
@CheckReturnValue
public <E extends Enum<E>> ActionTester combinations(
Class<E> attributeClass, ActionCombinationFactory<E> factory) throws Exception {
int attributesCount = attributeClass.getEnumConstants().length;
Preconditions.checkArgument(
attributesCount <= 30,
"Maximum attribute count is 30, more will overflow the max array size.");
Preconditions.checkArgument(attributesCount > 0, "Minimum attribute count is 1");
int count = (int) Math.pow(2, attributesCount);
Action firstAction = null;
for (int i = 0; i < count; i++) {
Action action = factory.generate(makeEnumSetInitializedTo(attributeClass, i));
actions.add(action);
// Check that creating the same action twice results in equal actions.
assertThat(
Actions.canBeShared(
actionKeyContext,
action,
factory.generate(makeEnumSetInitializedTo(attributeClass, i))))
.isTrue();
if (i == 0) {
firstAction = action;
}
}
// Sanity check that the count is correct.
assertThat(
Actions.canBeShared(
actionKeyContext,
firstAction,
factory.generate(makeEnumSetInitializedTo(attributeClass, count))))
.isTrue();
return this;
}
/** Checks that all actions are different. */
public void runTest() {
assertThat(actions).isNotEmpty();
for (int i = 0; i < actions.size(); i++) {
for (int j = i + 1; j < actions.size(); j++) {
assertWithMessage(i + " and " + j)
.that(Actions.canBeShared(actionKeyContext, actions.get(i), actions.get(j)))
.isFalse();
}
}
}
/**
* Tests that different actions have different keys. The attributeCount should specify how many
* different permutations the {@link ActionCombinationFactory} should generate.
*/
public static <E extends Enum<E>> void runTest(
Class<E> attributeClass,
ActionCombinationFactory<E> factory,
ActionKeyContext actionKeyContext)
throws Exception {
new ActionTester(actionKeyContext).combinations(attributeClass, factory).runTest();
}
private static <E extends Enum<E>> ImmutableSet<E> makeEnumSetInitializedTo(
Class<E> attributeClass, int seed) {
EnumSet<E> result = EnumSet.<E>noneOf(attributeClass);
BitSet b = BitSet.valueOf(new long[] {seed});
E[] attributes = attributeClass.getEnumConstants();
for (int i = 0; i < attributes.length; i++) {
if (b.get(i)) {
result.add(attributes[i]);
}
}
return Sets.immutableEnumSet(result);
}
}