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/*
* 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;
import com.google.javascript.jscomp.graph.FixedPointGraphTraversal;
import com.google.javascript.jscomp.graph.LinkedDirectedGraph;
import com.google.javascript.jscomp.graph.FixedPointGraphTraversal.EdgeCallback;
import com.google.javascript.jscomp.graph.DiGraph;
import junit.framework.TestCase;
/**
* Test for FixedPointGraphTraversal.
* @author nicksantos@google.com (Nick Santos)
*/
public class FixedPointGraphTraversalTest extends TestCase {
// The maximum value of a counter that counts as a "change"
// to the state of the graph, for the purposes of fixed-point
// computation.
private int maxChange = 0;
private class Counter {
int value = 0;
}
private class CounterIncrementer implements EdgeCallback<Counter, String> {
@Override
public boolean traverseEdge(Counter source, String e, Counter dest) {
dest.value++;
return dest.value <= maxChange;
}
}
private DiGraph<Counter, String> graph;
private Counter A, B, C, D, E;
private CounterIncrementer callback = new CounterIncrementer();
private FixedPointGraphTraversal<Counter, String> traversal =
new FixedPointGraphTraversal<Counter, String>(callback);
// Create a new graph of the following form:
//
// A
// / \
// | B
// / \ /
// C D
// \ /
// E
//
// with all edges pointing downwards, and an "up-edge" from E to D.
@Override
public void setUp() {
A = new Counter();
B = new Counter();
C = new Counter();
D = new Counter();
E = new Counter();
graph = LinkedDirectedGraph.create();
graph.createDirectedGraphNode(A);
graph.createDirectedGraphNode(B);
graph.createDirectedGraphNode(C);
graph.createDirectedGraphNode(D);
graph.createDirectedGraphNode(E);
graph.connect(A, "->", B);
graph.connect(A, "->", C);
graph.connect(A, "->", D);
graph.connect(B, "->", D);
graph.connect(C, "->", E);
graph.connect(D, "->", E);
graph.connect(E, "->", D);
}
public void testGraph1() {
maxChange = 0;
traversal.computeFixedPoint(graph, A);
assertEquals(0, A.value);
assertEquals(1, B.value);
assertEquals(1, C.value);
assertEquals(1, D.value);
assertEquals(0, E.value);
}
public void testGraph2() {
maxChange = 0;
traversal.computeFixedPoint(graph, D);
assertEquals(0, A.value);
assertEquals(0, B.value);
assertEquals(0, C.value);
assertEquals(0, D.value);
assertEquals(1, E.value);
}
public void testGraph3() {
maxChange = 1;
traversal.computeFixedPoint(graph, A);
assertEquals(0, A.value);
assertEquals(1, B.value);
assertEquals(1, C.value);
assertEquals(3, D.value);
assertEquals(2, E.value);
}
public void testGraph4() {
maxChange = 1;
traversal.computeFixedPoint(graph, D);
assertEquals(0, A.value);
assertEquals(0, B.value);
assertEquals(0, C.value);
assertEquals(1, D.value);
assertEquals(2, E.value);
}
public void testGraph5() {
maxChange = 5;
traversal.computeFixedPoint(graph, A);
assertEquals(0, A.value);
assertEquals(1, B.value);
assertEquals(1, C.value);
assertEquals(6, D.value);
assertEquals(5, E.value);
}
public void testGraph6() {
maxChange = 5;
traversal.computeFixedPoint(graph, B);
assertEquals(0, A.value);
assertEquals(0, B.value);
assertEquals(0, C.value);
assertEquals(6, D.value);
assertEquals(5, E.value);
}
public void testGraph8() {
maxChange = 2;
traversal.computeFixedPoint(graph, A);
try {
traversal = new FixedPointGraphTraversal<Counter, String>(
new EdgeCallback<Counter, String>() {
@Override
public boolean traverseEdge(Counter source, String e, Counter dest) {
return true;
}
});
traversal.computeFixedPoint(graph, A);
fail("Expecting Error: " +
FixedPointGraphTraversal.NON_HALTING_ERROR_MSG);
} catch (IllegalStateException e) {
assertEquals(e.getMessage(),
FixedPointGraphTraversal.NON_HALTING_ERROR_MSG);
}
}
public void testGraph9() {
maxChange = 0;
// when the graph traversal is done for the whole graph, we're actually
// counting the number of "in" edges for each node.
traversal.computeFixedPoint(graph);
assertEquals(0, A.value);
assertEquals(1, B.value);
assertEquals(1, C.value);
assertEquals(3, D.value);
assertEquals(2, E.value);
}
public void testGraph10() {
// Test a graph with self-edges.
maxChange = 5;
A = new Counter();
B = new Counter();
graph = LinkedDirectedGraph.create();
graph.createDirectedGraphNode(A);
graph.createDirectedGraphNode(B);
graph.connect(A, "->", A);
graph.connect(A, "->", B);
traversal.computeFixedPoint(graph);
assertEquals(6, A.value);
assertEquals(6, B.value);
}
}
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