documentation.federated.computer/node_modules/dependency-graph/specs/dep_graph_spec.js

var dep_graph = require("../lib/dep_graph");
var DepGraph = dep_graph.DepGraph;

describe("DepGraph", function () {
  it("should be able to add/remove nodes", function () {
    var graph = new DepGraph();

    graph.addNode("Foo");
    graph.addNode("Bar");

    expect(graph.hasNode("Foo")).toBeTrue();
    expect(graph.hasNode("Bar")).toBeTrue();
    expect(graph.hasNode("NotThere")).toBeFalse();

    graph.removeNode("Bar");

    expect(graph.hasNode("Bar")).toBeFalse();
  });

  it("should calculate its size", function () {
    var graph = new DepGraph();

    expect(graph.size()).toBe(0);

    graph.addNode("Foo");
    graph.addNode("Bar");

    expect(graph.size()).toBe(2);

    graph.removeNode("Bar");

    expect(graph.size()).toBe(1);
  });

  it("should treat the node data parameter as optional and use the node name as data if node data was not given", function () {
    var graph = new DepGraph();

    graph.addNode("Foo");

    expect(graph.getNodeData("Foo")).toBe("Foo");
  });

  it("should be able to associate a node name with data on node add", function () {
    var graph = new DepGraph();

    graph.addNode("Foo", "data");

    expect(graph.getNodeData("Foo")).toBe("data");
  });

  it("should be able to add undefined as node data", function () {
    var graph = new DepGraph();

    graph.addNode("Foo", undefined);

    expect(graph.getNodeData("Foo")).toBeUndefined();
  });

  it("should return true when using hasNode with a node which has falsy data", function () {
    var graph = new DepGraph();

    var falsyData = ["", 0, null, undefined, false];
    graph.addNode("Foo");

    falsyData.forEach(function (data) {
      graph.setNodeData("Foo", data);

      expect(graph.hasNode("Foo")).toBeTrue();

      // Just an extra check to make sure that the saved data is correct
      expect(graph.getNodeData("Foo")).toBe(data);
    });
  });

  it("should be able to set data after a node was added", function () {
    var graph = new DepGraph();

    graph.addNode("Foo", "data");
    graph.setNodeData("Foo", "data2");

    expect(graph.getNodeData("Foo")).toBe("data2");
  });

  it("should throw an error if we try to set data for a non-existing node", function () {
    var graph = new DepGraph();

    expect(function () {
      graph.setNodeData("Foo", "data");
    }).toThrow(new Error("Node does not exist: Foo"));
  });

  it("should throw an error if the node does not exists and we try to get data", function () {
    var graph = new DepGraph();

    expect(function () {
      graph.getNodeData("Foo");
    }).toThrow(new Error("Node does not exist: Foo"));
  });

  it("should do nothing if creating a node that already exists", function () {
    var graph = new DepGraph();

    graph.addNode("a");
    graph.addNode("b");

    graph.addDependency("a", "b");

    graph.addNode("a");

    expect(graph.dependenciesOf("a")).toEqual(["b"]);
  });

  it("should do nothing if removing a node that does not exist", function () {
    var graph = new DepGraph();

    graph.addNode("a");
    expect(graph.hasNode("a")).toBeTrue();

    graph.removeNode("a");
    expect(graph.hasNode("Foo")).toBeFalse();

    graph.removeNode("a");
    expect(graph.hasNode("Foo")).toBeFalse();
  });

  it("should be able to add dependencies between nodes", function () {
    var graph = new DepGraph();

    graph.addNode("a");
    graph.addNode("b");
    graph.addNode("c");

    graph.addDependency("a", "b");
    graph.addDependency("a", "c");

    expect(graph.dependenciesOf("a")).toEqual(["b", "c"]);
  });

  it("should find entry nodes", function () {
    var graph = new DepGraph();

    graph.addNode("a");
    graph.addNode("b");
    graph.addNode("c");

    graph.addDependency("a", "b");
    graph.addDependency("a", "c");

    expect(graph.entryNodes()).toEqual(["a"]);
  });

  it("should throw an error if a node does not exist and a dependency is added", function () {
    var graph = new DepGraph();

    graph.addNode("a");

    expect(function () {
      graph.addDependency("a", "b");
    }).toThrow(new Error("Node does not exist: b"));
  });

  it("should detect cycles", function () {
    var graph = new DepGraph();

    graph.addNode("a");
    graph.addNode("b");
    graph.addNode("c");
    graph.addNode("d");

    graph.addDependency("a", "b");
    graph.addDependency("b", "c");
    graph.addDependency("c", "a");
    graph.addDependency("d", "a");

    expect(function () {
      graph.dependenciesOf("b");
    }).toThrow(new dep_graph.DepGraphCycleError(["b", "c", "a", "b"]));
  });

  it("should allow cycles when configured", function () {
    var graph = new DepGraph({ circular: true });

    graph.addNode("a");
    graph.addNode("b");
    graph.addNode("c");
    graph.addNode("d");

    graph.addDependency("a", "b");
    graph.addDependency("b", "c");
    graph.addDependency("c", "a");
    graph.addDependency("d", "a");

    expect(graph.dependenciesOf("b")).toEqual(["a", "c"]);
    expect(graph.overallOrder()).toEqual(["c", "b", "a", "d"]);
  });

  it(
    "should include all nodes in overall order even from " +
    "cycles in disconnected subgraphs when circular is true",
    function () {
      var graph = new DepGraph({ circular: true });

      graph.addNode("2a");
      graph.addNode("2b");
      graph.addNode("2c");
      graph.addDependency("2a", "2b");
      graph.addDependency("2b", "2c");
      graph.addDependency("2c", "2a");

      graph.addNode("1a");
      graph.addNode("1b");
      graph.addNode("1c");
      graph.addNode("1d");
      graph.addNode("1e");

      graph.addDependency("1a", "1b");
      graph.addDependency("1a", "1c");
      graph.addDependency("1b", "1c");
      graph.addDependency("1c", "1d");

      expect(graph.overallOrder()).toEqual([
        "1d",
        "1c",
        "1b",
        "1a",
        "1e",
        "2c",
        "2b",
        "2a"
      ]);
    }
  );

  it("should detect cycles in overall order", function () {
    var graph = new DepGraph();

    graph.addNode("a");
    graph.addNode("b");
    graph.addNode("c");
    graph.addNode("d");

    graph.addDependency("a", "b");
    graph.addDependency("b", "c");
    graph.addDependency("c", "a");
    graph.addDependency("d", "a");

    expect(function () {
      graph.overallOrder();
    }).toThrow(new dep_graph.DepGraphCycleError(["a", "b", "c", "a"]));
  });

  it("should detect cycles in overall order when all nodes have dependants (incoming edges)", function () {
    var graph = new DepGraph();

    graph.addNode("a");
    graph.addNode("b");
    graph.addNode("c");

    graph.addDependency("a", "b");
    graph.addDependency("b", "c");
    graph.addDependency("c", "a");

    expect(function () {
      graph.overallOrder();
    }).toThrow(new dep_graph.DepGraphCycleError(["a", "b", "c", "a"]));
  });

  it(
    "should detect cycles in overall order when there are several " +
    "disconnected subgraphs (with one that does not have a cycle",
    function () {
      var graph = new DepGraph();

      graph.addNode("a_1");
      graph.addNode("a_2");
      graph.addNode("b_1");
      graph.addNode("b_2");
      graph.addNode("b_3");

      graph.addDependency("a_1", "a_2");
      graph.addDependency("b_1", "b_2");
      graph.addDependency("b_2", "b_3");
      graph.addDependency("b_3", "b_1");

      expect(function () {
        graph.overallOrder();
      }).toThrow(
        new dep_graph.DepGraphCycleError(["b_1", "b_2", "b_3", "b_1"])
      );
    }
  );

  it("should retrieve dependencies and dependants in the correct order", function () {
    var graph = new DepGraph();

    graph.addNode("a");
    graph.addNode("b");
    graph.addNode("c");
    graph.addNode("d");

    graph.addDependency("a", "d");
    graph.addDependency("a", "b");
    graph.addDependency("b", "c");
    graph.addDependency("d", "b");

    expect(graph.dependenciesOf("a")).toEqual(["c", "b", "d"]);
    expect(graph.dependenciesOf("b")).toEqual(["c"]);
    expect(graph.dependenciesOf("c")).toEqual([]);
    expect(graph.dependenciesOf("d")).toEqual(["c", "b"]);

    expect(graph.dependantsOf("a")).toEqual([]);
    expect(graph.dependantsOf("b")).toEqual(["a", "d"]);
    expect(graph.dependantsOf("c")).toEqual(["a", "d", "b"]);
    expect(graph.dependantsOf("d")).toEqual(["a"]);

    // check the alias "dependentsOf"
    expect(graph.dependentsOf("a")).toEqual([]);
    expect(graph.dependentsOf("b")).toEqual(["a", "d"]);
    expect(graph.dependentsOf("c")).toEqual(["a", "d", "b"]);
    expect(graph.dependentsOf("d")).toEqual(["a"]);
  });

  it("should be able to retrieve direct dependencies/dependants", function () {
    var graph = new DepGraph();

    graph.addNode("a");
    graph.addNode("b");
    graph.addNode("c");
    graph.addNode("d");

    graph.addDependency("a", "d");
    graph.addDependency("a", "b");
    graph.addDependency("b", "c");
    graph.addDependency("d", "b");

    expect(graph.directDependenciesOf("a")).toEqual(["d", "b"]);
    expect(graph.directDependenciesOf("b")).toEqual(["c"]);
    expect(graph.directDependenciesOf("c")).toEqual([]);
    expect(graph.directDependenciesOf("d")).toEqual(["b"]);

    expect(graph.directDependantsOf("a")).toEqual([]);
    expect(graph.directDependantsOf("b")).toEqual(["a", "d"]);
    expect(graph.directDependantsOf("c")).toEqual(["b"]);
    expect(graph.directDependantsOf("d")).toEqual(["a"]);

    // check the alias "directDependentsOf"
    expect(graph.directDependentsOf("a")).toEqual([]);
    expect(graph.directDependentsOf("b")).toEqual(["a", "d"]);
    expect(graph.directDependentsOf("c")).toEqual(["b"]);
    expect(graph.directDependentsOf("d")).toEqual(["a"]);
  });

  it("should be able to resolve the overall order of things", function () {
    var graph = new DepGraph();

    graph.addNode("a");
    graph.addNode("b");
    graph.addNode("c");
    graph.addNode("d");
    graph.addNode("e");

    graph.addDependency("a", "b");
    graph.addDependency("a", "c");
    graph.addDependency("b", "c");
    graph.addDependency("c", "d");

    expect(graph.overallOrder()).toEqual(["d", "c", "b", "a", "e"]);
  });

  it('should be able to only retrieve the "leaves" in the overall order', function () {
    var graph = new DepGraph();

    graph.addNode("a");
    graph.addNode("b");
    graph.addNode("c");
    graph.addNode("d");
    graph.addNode("e");

    graph.addDependency("a", "b");
    graph.addDependency("a", "c");
    graph.addDependency("b", "c");
    graph.addDependency("c", "d");

    expect(graph.overallOrder(true)).toEqual(["d", "e"]);
  });

  it("should be able to give the overall order for a graph with several disconnected subgraphs", function () {
    var graph = new DepGraph();

    graph.addNode("a_1");
    graph.addNode("a_2");
    graph.addNode("b_1");
    graph.addNode("b_2");
    graph.addNode("b_3");

    graph.addDependency("a_1", "a_2");
    graph.addDependency("b_1", "b_2");
    graph.addDependency("b_2", "b_3");

    expect(graph.overallOrder()).toEqual(["a_2", "a_1", "b_3", "b_2", "b_1"]);
  });

  it("should give an empty overall order for an empty graph", function () {
    var graph = new DepGraph();

    expect(graph.overallOrder()).toEqual([]);
  });

  it("should still work after nodes are removed", function () {
    var graph = new DepGraph();

    graph.addNode("a");
    graph.addNode("b");
    graph.addNode("c");
    graph.addDependency("a", "b");
    graph.addDependency("b", "c");

    expect(graph.dependenciesOf("a")).toEqual(["c", "b"]);

    graph.removeNode("c");

    expect(graph.dependenciesOf("a")).toEqual(["b"]);
  });

  it("should clone an empty graph", function () {
    var graph = new DepGraph();
    expect(graph.size()).toEqual(0);
    var cloned = graph.clone();
    expect(cloned.size()).toEqual(0);

    expect(graph === cloned).toBeFalse();
  });

  it("should clone a non-empty graph", function () {
    var graph = new DepGraph();

    graph.addNode("a");
    graph.addNode("b");
    graph.addNode("c");
    graph.addDependency("a", "b");
    graph.addDependency("b", "c");

    var cloned = graph.clone();

    expect(graph === cloned).toBeFalse();
    expect(cloned.hasNode("a")).toBeTrue();
    expect(cloned.hasNode("b")).toBeTrue();
    expect(cloned.hasNode("c")).toBeTrue();
    expect(cloned.dependenciesOf("a")).toEqual(["c", "b"]);
    expect(cloned.dependantsOf("c")).toEqual(["a", "b"]);

    // Changes to the original graph shouldn't affect the clone
    graph.removeNode("c");
    expect(graph.dependenciesOf("a")).toEqual(["b"]);
    expect(cloned.dependenciesOf("a")).toEqual(["c", "b"]);

    graph.addNode("d");
    graph.addDependency("b", "d");
    expect(graph.dependenciesOf("a")).toEqual(["d", "b"]);
    expect(cloned.dependenciesOf("a")).toEqual(["c", "b"]);
  });

  it("should only be a shallow clone", function () {
    var graph = new DepGraph();

    var data = { a: 42 };
    graph.addNode("a", data);

    var cloned = graph.clone();
    expect(graph === cloned).toBeFalse();
    expect(graph.getNodeData("a") === cloned.getNodeData("a")).toBeTrue();

    graph.getNodeData("a").a = 43;
    expect(cloned.getNodeData("a").a).toBe(43);

    cloned.setNodeData("a", { a: 42 });
    expect(cloned.getNodeData("a").a).toBe(42);
    expect(graph.getNodeData("a") === cloned.getNodeData("a")).toBeFalse();
  });
});

describe("DepGraph Performance", function () {
  it("should not exceed max call stack with a very deep graph", function () {
    var g = new DepGraph();
    var expected = [];
    for (var i = 0; i < 100000; i++) {
      var istr = i.toString();
      g.addNode(istr);
      expected.push(istr);
      if (i > 0) {
        g.addDependency(istr, (i - 1).toString());
      }
    }
    var order = g.overallOrder();
    expect(order).toEqual(expected);
  });

  it("should run an a reasonable amount of time for a very large graph", function () {
    var randInt = function (min, max) {
      return Math.floor(Math.random() * (max - min + 1)) + min;
    };
    var g = new DepGraph();
    var nodes = [];
    // Create a graph with 100000 nodes in it with 10 random connections to
    // lower numbered nodes
    for (var i = 0; i < 100000; i++) {
      nodes.push(i.toString());
      g.addNode(i.toString());
      for (var j = 0; j < 10; j++) {
        var dep = randInt(0, i);
        if (i !== dep) {
          g.addDependency(i.toString(), dep.toString());
        }
      }
    }
    var start = new Date().getTime();
    g.overallOrder();
    var end = new Date().getTime();
    expect(start - end).toBeLessThan(1000);
  });
});

describe("DepGraphCycleError", function () {
  var DepGraphCycleError = dep_graph.DepGraphCycleError;

  it("should have a message", function () {
    var err = new DepGraphCycleError(["a", "b", "c", "a"]);
    expect(err.message).toEqual("Dependency Cycle Found: a -> b -> c -> a");
  });

  it("should be an instanceof DepGraphCycleError", function () {
    var err = new DepGraphCycleError(["a", "b", "c", "a"]);
    expect(err instanceof DepGraphCycleError).toBeTrue();
    expect(err instanceof Error).toBeTrue();
  });

  it("should have a cyclePath", function () {
    var cyclePath = ["a", "b", "c", "a"];
    var err = new DepGraphCycleError(cyclePath);
    expect(err.cyclePath).toEqual(cyclePath);
  });
});