test: add tests for FamousGraphLibrary

Gvisual/test/gvisual/FamousGraphLibraryTest.java

@@ -0,0 +1,184 @@
+package gvisual;
+
+import edu.uci.ics.jung.graph.Graph;
+import org.junit.Test;
+
+import java.util.LinkedHashMap;
+
+import static org.junit.Assert.*;
+
+/**
+ * Tests for {@link FamousGraphLibrary} — verifies structural properties
+ * of each famous named graph.
+ */
+public class FamousGraphLibraryTest {
+
+    // ── Petersen Graph ──────────────────────────────────────
+
+    @Test
+    public void petersen_has_10_vertices_15_edges() {
+        Graph<String, Edge> g = FamousGraphLibrary.petersen();
+        assertEquals(10, g.getVertexCount());
+        assertEquals(15, g.getEdgeCount());
+        // Petersen graph is 3-regular
+        for (String v : g.getVertices()) {
+            assertEquals("Petersen is 3-regular", 3, g.degree(v));
+        }
+    }
+
+    // ── Zachary's Karate Club ───────────────────────────────
+
+    @Test
+    public void karate_has_34_vertices_78_edges() {
+        Graph<String, Edge> g = FamousGraphLibrary.karateClub();
+        assertEquals(34, g.getVertexCount());
+        assertEquals(78, g.getEdgeCount());
+    }
+
+    // ── Königsberg Bridges ──────────────────────────────────
+
+    @Test
+    public void konigsberg_has_4_vertices_7_edges() {
+        Graph<String, Edge> g = FamousGraphLibrary.konigsberg();
+        assertEquals(4, g.getVertexCount());
+        assertEquals(7, g.getEdgeCount());
+    }
+
+    // ── K₃₃ ────────────────────────────────────────────────
+
+    @Test
+    public void k33_has_6_vertices_9_edges() {
+        Graph<String, Edge> g = FamousGraphLibrary.k33();
+        assertEquals(6, g.getVertexCount());
+        assertEquals(9, g.getEdgeCount());
+    }
+
+    // ── Frucht Graph ────────────────────────────────────────
+
+    @Test
+    public void frucht_has_12_vertices_18_edges() {
+        Graph<String, Edge> g = FamousGraphLibrary.frucht();
+        assertEquals(12, g.getVertexCount());
+        assertEquals(18, g.getEdgeCount());
+        // Frucht is 3-regular (cubic)
+        for (String v : g.getVertices()) {
+            assertEquals("Frucht is cubic", 3, g.degree(v));
+        }
+    }
+
+    // ── Heawood Graph ───────────────────────────────────────
+
+    @Test
+    public void heawood_has_14_vertices_21_edges() {
+        Graph<String, Edge> g = FamousGraphLibrary.heawood();
+        assertEquals(14, g.getVertexCount());
+        assertEquals(21, g.getEdgeCount());
+        // Heawood is 3-regular
+        for (String v : g.getVertices()) {
+            assertEquals("Heawood is cubic", 3, g.degree(v));
+        }
+    }
+
+    // ── Dodecahedron ────────────────────────────────────────
+
+    @Test
+    public void dodecahedron_has_20_vertices_30_edges() {
+        Graph<String, Edge> g = FamousGraphLibrary.dodecahedron();
+        assertEquals(20, g.getVertexCount());
+        assertEquals(30, g.getEdgeCount());
+        // Dodecahedron is 3-regular
+        for (String v : g.getVertices()) {
+            assertEquals("Dodecahedron is cubic", 3, g.degree(v));
+        }
+    }
+
+    // ── Tutte Graph ─────────────────────────────────────────
+
+    @Test
+    public void tutte_has_46_vertices_69_edges() {
+        Graph<String, Edge> g = FamousGraphLibrary.tutte();
+        assertEquals(46, g.getVertexCount());
+        assertEquals(69, g.getEdgeCount());
+        // Tutte graph is 3-regular
+        for (String v : g.getVertices()) {
+            assertEquals("Tutte is cubic", 3, g.degree(v));
+        }
+    }
+
+    // ── Florentine Families ─────────────────────────────────
+
+    @Test
+    public void florentine_has_15_vertices() {
+        Graph<String, Edge> g = FamousGraphLibrary.florentine();
+        assertEquals(15, g.getVertexCount());
+        assertTrue(g.getEdgeCount() > 0);
+        // Medici should be a high-degree hub
+        assertTrue("Medici is a hub", g.degree("Medici") >= 5);
+    }
+
+    // ── Diamond Graph ───────────────────────────────────────
+
+    @Test
+    public void diamond_has_4_vertices_5_edges() {
+        Graph<String, Edge> g = FamousGraphLibrary.diamond();
+        assertEquals(4, g.getVertexCount());
+        assertEquals(5, g.getEdgeCount());
+    }
+
+    // ── Bull Graph ──────────────────────────────────────────
+
+    @Test
+    public void bull_has_5_vertices_5_edges() {
+        Graph<String, Edge> g = FamousGraphLibrary.bull();
+        assertEquals(5, g.getVertexCount());
+        assertEquals(5, g.getEdgeCount());
+    }
+
+    // ── Butterfly Graph ─────────────────────────────────────
+
+    @Test
+    public void butterfly_has_5_vertices_6_edges() {
+        Graph<String, Edge> g = FamousGraphLibrary.butterfly();
+        assertEquals(5, g.getVertexCount());
+        assertEquals(6, g.getEdgeCount());
+    }
+
+    // ── Catalog ─────────────────────────────────────────────
+
+    @Test
+    public void catalog_contains_all_12_graphs() {
+        LinkedHashMap<String, String> cat = FamousGraphLibrary.catalog();
+        assertEquals(12, cat.size());
+        assertTrue(cat.containsKey("petersen"));
+        assertTrue(cat.containsKey("karate"));
+        assertTrue(cat.containsKey("butterfly"));
+    }
+
+    // ── byName lookup ───────────────────────────────────────
+
+    @Test
+    public void byName_case_insensitive() {
+        assertNotNull(FamousGraphLibrary.byName("PETERSEN"));
+        assertNotNull(FamousGraphLibrary.byName("Petersen"));
+        assertNotNull(FamousGraphLibrary.byName("petersen"));
+    }
+
+    @Test
+    public void byName_unknown_returns_null() {
+        assertNull(FamousGraphLibrary.byName("nonexistent"));
+    }
+
+    @Test
+    public void byName_null_returns_null() {
+        assertNull(FamousGraphLibrary.byName(null));
+    }
+
+    @Test
+    public void byName_all_catalog_entries_resolve() {
+        for (String name : FamousGraphLibrary.catalog().keySet()) {
+            Graph<String, Edge> g = FamousGraphLibrary.byName(name);
+            assertNotNull("byName should resolve: " + name, g);
+            assertTrue("Graph should have vertices: " + name, g.getVertexCount() > 0);
+        }
+    }
+}