public void MergedPath_Throws()
{
// ReSharper disable ReturnValueOfPureMethodIsNotUsed
// ReSharper disable AssignNullToNotNullAttribute
var recorder = new EdgePredecessorRecorderObserver <int, Edge <int> >();
Assert.Throws <ArgumentNullException>(
() => recorder.MergedPath(null, new Dictionary <Edge <int>, GraphColor>()));
Assert.Throws <ArgumentNullException>(
() => recorder.MergedPath(new Edge <int>(1, 2), null));
Assert.Throws <ArgumentNullException>(
() => recorder.MergedPath(null, null));
// ReSharper restore AssignNullToNotNullAttribute
var edge = new Edge <int>(1, 2);
Assert.Throws <KeyNotFoundException>(
() => recorder.MergedPath(edge, new Dictionary <Edge <int>, GraphColor>()));
// ReSharper restore ReturnValueOfPureMethodIsNotUsed
}
public void MergedPath()
{
{
var recorder = new EdgePredecessorRecorderObserver <int, Edge <int> >();
var graph = new AdjacencyGraph <int, Edge <int> >();
var dfs = new EdgeDepthFirstSearchAlgorithm <int, Edge <int> >(graph);
using (recorder.Attach(dfs))
{
dfs.Compute();
var edge12 = new Edge <int>(1, 2);
var colors = new Dictionary <Edge <int>, GraphColor>
{
[edge12] = GraphColor.Black
};
// Not in the graph and edge marked as already used!
CollectionAssert.IsEmpty(recorder.MergedPath(edge12, colors));
// Not in the graph => return the edge itself
colors[edge12] = GraphColor.White;
CollectionAssert.AreEqual(
new[] { edge12 },
recorder.MergedPath(edge12, colors));
}
}
{
var recorder = new EdgePredecessorRecorderObserver <int, Edge <int> >();
// Graph without cycle
var edge12 = new Edge <int>(1, 2);
var edge13 = new Edge <int>(1, 3);
var edge14 = new Edge <int>(1, 4);
var edge24 = new Edge <int>(2, 4);
var edge31 = new Edge <int>(3, 1);
var edge33 = new Edge <int>(3, 3);
var edge34 = new Edge <int>(3, 4);
var graph = new AdjacencyGraph <int, Edge <int> >();
graph.AddVerticesAndEdgeRange(new[]
{
edge12, edge13, edge14, edge24, edge31, edge33, edge34
});
var dfs = new EdgeDepthFirstSearchAlgorithm <int, Edge <int> >(graph);
using (recorder.Attach(dfs))
{
dfs.Compute();
Dictionary <Edge <int>, GraphColor> colors = graph.Edges.ToDictionary(
edge => edge,
_ => GraphColor.White);
CollectionAssert.AreEqual(
new[] { edge12, edge24 },
recorder.MergedPath(edge24, colors));
// Already used
CollectionAssert.IsEmpty(recorder.MergedPath(edge24, colors));
CollectionAssert.AreEqual(
new[] { edge13, edge31 },
recorder.MergedPath(edge31, colors));
}
}
{
var recorder = new EdgePredecessorRecorderObserver <int, Edge <int> >();
// Graph with cycle
var edge12 = new Edge <int>(1, 2);
var edge13 = new Edge <int>(1, 3);
var edge14 = new Edge <int>(1, 4);
var edge24 = new Edge <int>(2, 4);
var edge31 = new Edge <int>(3, 1);
var edge33 = new Edge <int>(3, 3);
var edge34 = new Edge <int>(3, 4);
var edge41 = new Edge <int>(4, 1);
var graph = new AdjacencyGraph <int, Edge <int> >();
graph.AddVerticesAndEdgeRange(new[]
{
edge12, edge13, edge14, edge24, edge31, edge33, edge34, edge41
});
var dfs = new EdgeDepthFirstSearchAlgorithm <int, Edge <int> >(graph);
using (recorder.Attach(dfs))
{
dfs.Compute();
Dictionary <Edge <int>, GraphColor> colors = graph.Edges.ToDictionary(
edge => edge,
_ => GraphColor.White);
CollectionAssert.AreEqual(
new[] { edge12, edge24, edge41 },
recorder.MergedPath(edge41, colors));
// Already used
CollectionAssert.IsEmpty(recorder.MergedPath(edge41, colors));
CollectionAssert.AreEqual(
new[] { edge13, edge33, edge34 },
recorder.MergedPath(edge34, colors));
}
}
}
