1 files changed, 69 insertions, 0 deletions
diff --git a/container-di/src/test/java/com/yahoo/container/di/componentgraph/cycle/GraphTest.java b/container-di/src/test/java/com/yahoo/container/di/componentgraph/cycle/GraphTest.java
new file mode 100644
index 00000000000..588c1e30ffe
--- /dev/null
+++ b/container-di/src/test/java/com/yahoo/container/di/componentgraph/cycle/GraphTest.java
@@ -0,0 +1,69 @@
+/*
+ * Copyright 2019 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+ */
+
+package com.yahoo.container.di.componentgraph.cycle;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+import static com.yahoo.container.di.componentgraph.cycle.GraphTest.Vertices.A;
+import static com.yahoo.container.di.componentgraph.cycle.GraphTest.Vertices.B;
+import static com.yahoo.container.di.componentgraph.cycle.GraphTest.Vertices.C;
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.Matchers.contains;
+import static org.hamcrest.Matchers.containsInAnyOrder;
+import static org.hamcrest.Matchers.empty;
+import static org.junit.Assert.assertThat;
+
+/**
+ * @author gjoranv
+ */
+public class GraphTest {
+
+    enum Vertices {A, B, C}
+
+    @Rule
+    public ExpectedException expectedException = ExpectedException.none();
+
+    @Test
+    public void vertices_and_edges_are_added_and_can_be_retrieved() {
+        var graph = new Graph<Vertices>();
+        graph.edge(A, B);
+        graph.edge(B, C);
+        graph.edge(A, C);
+
+        assertThat(graph.getVertices().size(), is(3));
+        assertThat(graph.getAdjacent(A), containsInAnyOrder(B, C));
+        assertThat(graph.getAdjacent(B), containsInAnyOrder(C));
+        assertThat(graph.getAdjacent(C), empty());
+    }
+
+    @Test
+    public void null_vertices_are_not_allowed() {
+        var graph = new Graph<Vertices>();
+
+        expectedException.expect(IllegalArgumentException.class);
+        expectedException.expectMessage("Null vertices are not allowed");
+        graph.edge(A, null);
+    }
+
+    @Test
+    public void duplicate_edges_are_ignored() {
+        var graph = new Graph<Vertices>();
+        graph.edge(A, B);
+        graph.edge(A, B);
+
+        assertThat(graph.getAdjacent(A).size(), is(1));
+    }
+
+    @Test
+    public void self_edges_are_allowed() {
+        var graph = new Graph<Vertices>();
+        graph.edge(A, A);
+
+        assertThat(graph.getAdjacent(A), contains(A));
+    }
+
+}