1 files changed, 131 insertions, 0 deletions
diff --git a/compiler/rustc_data_structures/src/graph/implementation/tests.rs b/compiler/rustc_data_structures/src/graph/implementation/tests.rs
new file mode 100644
index 00000000000..e4e4d0d44ba
--- /dev/null
+++ b/compiler/rustc_data_structures/src/graph/implementation/tests.rs
@@ -0,0 +1,131 @@
+use crate::graph::implementation::*;
+use std::fmt::Debug;
+
+type TestGraph = Graph<&'static str, &'static str>;
+
+fn create_graph() -> TestGraph {
+    let mut graph = Graph::new();
+
+    // Create a simple graph
+    //
+    //          F
+    //          |
+    //          V
+    //    A --> B --> C
+    //          |     ^
+    //          v     |
+    //          D --> E
+
+    let a = graph.add_node("A");
+    let b = graph.add_node("B");
+    let c = graph.add_node("C");
+    let d = graph.add_node("D");
+    let e = graph.add_node("E");
+    let f = graph.add_node("F");
+
+    graph.add_edge(a, b, "AB");
+    graph.add_edge(b, c, "BC");
+    graph.add_edge(b, d, "BD");
+    graph.add_edge(d, e, "DE");
+    graph.add_edge(e, c, "EC");
+    graph.add_edge(f, b, "FB");
+
+    return graph;
+}
+
+#[test]
+fn each_node() {
+    let graph = create_graph();
+    let expected = ["A", "B", "C", "D", "E", "F"];
+    graph.each_node(|idx, node| {
+        assert_eq!(&expected[idx.0], graph.node_data(idx));
+        assert_eq!(expected[idx.0], node.data);
+        true
+    });
+}
+
+#[test]
+fn each_edge() {
+    let graph = create_graph();
+    let expected = ["AB", "BC", "BD", "DE", "EC", "FB"];
+    graph.each_edge(|idx, edge| {
+        assert_eq!(expected[idx.0], edge.data);
+        true
+    });
+}
+
+fn test_adjacent_edges<N: PartialEq + Debug, E: PartialEq + Debug>(
+    graph: &Graph<N, E>,
+    start_index: NodeIndex,
+    start_data: N,
+    expected_incoming: &[(E, N)],
+    expected_outgoing: &[(E, N)],
+) {
+    assert!(graph.node_data(start_index) == &start_data);
+
+    let mut counter = 0;
+    for (edge_index, edge) in graph.incoming_edges(start_index) {
+        assert!(counter < expected_incoming.len());
+        debug!(
+            "counter={:?} expected={:?} edge_index={:?} edge={:?}",
+            counter, expected_incoming[counter], edge_index, edge
+        );
+        match expected_incoming[counter] {
+            (ref e, ref n) => {
+                assert!(e == &edge.data);
+                assert!(n == graph.node_data(edge.source()));
+                assert!(start_index == edge.target);
+            }
+        }
+        counter += 1;
+    }
+    assert_eq!(counter, expected_incoming.len());
+
+    let mut counter = 0;
+    for (edge_index, edge) in graph.outgoing_edges(start_index) {
+        assert!(counter < expected_outgoing.len());
+        debug!(
+            "counter={:?} expected={:?} edge_index={:?} edge={:?}",
+            counter, expected_outgoing[counter], edge_index, edge
+        );
+        match expected_outgoing[counter] {
+            (ref e, ref n) => {
+                assert!(e == &edge.data);
+                assert!(start_index == edge.source);
+                assert!(n == graph.node_data(edge.target));
+            }
+        }
+        counter += 1;
+    }
+    assert_eq!(counter, expected_outgoing.len());
+}
+
+#[test]
+fn each_adjacent_from_a() {
+    let graph = create_graph();
+    test_adjacent_edges(&graph, NodeIndex(0), "A", &[], &[("AB", "B")]);
+}
+
+#[test]
+fn each_adjacent_from_b() {
+    let graph = create_graph();
+    test_adjacent_edges(
+        &graph,
+        NodeIndex(1),
+        "B",
+        &[("FB", "F"), ("AB", "A")],
+        &[("BD", "D"), ("BC", "C")],
+    );
+}
+
+#[test]
+fn each_adjacent_from_c() {
+    let graph = create_graph();
+    test_adjacent_edges(&graph, NodeIndex(2), "C", &[("EC", "E"), ("BC", "B")], &[]);
+}
+
+#[test]
+fn each_adjacent_from_d() {
+    let graph = create_graph();
+    test_adjacent_edges(&graph, NodeIndex(3), "D", &[("BD", "B")], &[("DE", "E")]);
+}