/*
 * Copyright 2008 The Closure Compiler Authors.
 *
 * 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.javascript.jscomp.graph;

import com.google.javascript.jscomp.graph.GraphReachability;
import com.google.javascript.jscomp.graph.LinkedDirectedGraph;
import com.google.javascript.jscomp.graph.DiGraph;

import junit.framework.TestCase;

/**
 * Tests for {@link GraphReachability}.
 *
 */
public class GraphReachabilityTest extends TestCase {
  GraphReachability<String, String> reachability = null;
  DiGraph<String, String> graph = null;

  public void testSimple() {
    graph = LinkedDirectedGraph.create();
    graph.createNode("A");
    reachability = new GraphReachability<String, String>(graph);
    reachability.compute("A");
    assertReachable("A");

    graph.createNode("B");
    reachability = new GraphReachability<String, String>(graph);
    reachability.compute("A");
    assertReachable("A");
    assertNotReachable("B");

    graph.connect("A", "--->", "B");
    reachability = new GraphReachability<String, String>(graph);
    reachability.compute("B");
    assertNotReachable("A");
    assertReachable("B");

    graph.connect("B", "--->", "A");
    reachability = new GraphReachability<String, String>(graph);
    reachability.compute("B");
    assertReachable("A");
    assertReachable("B");

    graph.createNode("C");
    reachability = new GraphReachability<String, String>(graph);
    reachability.compute("A");
    assertReachable("A");
    assertReachable("B");
    assertNotReachable("C");

    graph.createNode("D");
    graph.connect("C", "--->", "D");
    reachability = new GraphReachability<String, String>(graph);
    reachability.compute("A");
    assertReachable("A");
    assertReachable("B");
    assertNotReachable("C");
    assertNotReachable("D");
    reachability.recompute("C");
    assertReachable("C");
    assertReachable("D");
  }

  public void assertReachable(String s) {
    assertSame(s + " should be reachable", graph.getNode(s).getAnnotation(),
        GraphReachability.REACHABLE);
  }

  public void assertNotReachable(String s) {
    assertNotSame(s + " should not be reachable",
        graph.getNode(s).getAnnotation(), GraphReachability.REACHABLE);
  }
}