abrolgo/graph/graph_test.go

package graph

import (
	"sort"
	"strings"
	"testing"
)

func TestNewGraph(t *testing.T) {
	g := NewGraph[int, int]()

	// Check if the graph is initialized correctly
	if g.v != 0 {
		t.Errorf("NewGraph() failed: expected v = 0, got v = %d", g.v)
	}
	if g.e != 0 {
		t.Errorf("NewGraph() failed: expected e = 0, got e = %d", g.e)
	}
	if len(g.adjacencyList) != 0 {
		t.Errorf("NewGraph() failed: expected empty adjacency list, got %v", g.adjacencyList)
	}
	if len(g.edges) != 0 {
		t.Errorf("NewGraph() failed: expected empty edges list, got %v", g.edges)
	}
}

func TestAddEdge(t *testing.T) {
	g := NewGraph[int, int]()

	// Add edges to the graph
	g.AddEdge(1, 2, 10)
	g.AddEdge(2, 3, 20)
	g.AddEdge(3, 4, 30)

	// Check if the edges are added correctly
	expectedV := 4
	if g.v != expectedV {
		t.Errorf("AddEdge() failed: expected v = %d, got v = %d", expectedV, g.v)
	}

	expectedE := 3
	if g.e != expectedE {
		t.Errorf("AddEdge() failed: expected e = %d, got e = %d", expectedE, g.e)
	}

	expectedAdjacencyList := map[int][]Edge[int, int]{
		1: {{1, 1, 2, 10}},
		2: {{1, 2, 1, 10}, {2, 2, 3, 20}},
		3: {{2, 3, 2, 20}, {3, 3, 4, 30}},
		4: {{3, 4, 3, 30}},
	}
	if !compareAdjacencyLists(g.adjacencyList, expectedAdjacencyList) {
		t.Errorf("AddEdge() failed: expected adjacency list = %v, got %v", expectedAdjacencyList, g.adjacencyList)
	}

	expectedEdges := []Edge[int, int]{
		{1, 1, 2, 10},
		{2, 2, 3, 20},
		{3, 3, 4, 30},
	}
	if !compareEdges(g.edges, expectedEdges) {
		t.Errorf("AddEdge() failed: expected edges list = %v, got %v", expectedEdges, g.edges)
	}
}

func compareAdjacencyLists(a, b map[int][]Edge[int, int]) bool {
	if len(a) != len(b) {
		return false
	}

	for key, valueA := range a {
		valueB, ok := b[key]
		if !ok || !compareEdges(valueA, valueB) {
			return false
		}
	}

	return true
}

func compareEdges(a, b []Edge[int, int]) bool {
	if len(a) != len(b) {
		return false
	}

	for i := 0; i < len(a); i++ {
		if a[i] != b[i] {
			return false
		}
	}

	return true
}

func TestGetNeighbors(t *testing.T) {
	// Create a new graph
	g := NewGraph[int, int]()

	// Add vertices and edges to the graph
	g.AddEdge(1, 2, 10)
	g.AddEdge(1, 3, 20)
	g.AddEdge(2, 3, 30)

	// Test GetNeighbors for vertex 1
	neighbors := g.GetNeighbors(1)
	expectedNeighbors := []Edge[int, int]{{ID: 1, src: 1, dest: 2, weight: 10}, {ID: 2, src: 1, dest: 3, weight: 20}}
	if !equalEdges(neighbors, expectedNeighbors) {
		t.Errorf("GetNeighbors() failed for vertex 1: expected %v, got %v", expectedNeighbors, neighbors)
	}

	// Test GetNeighbors for vertex 2
	neighbors = g.GetNeighbors(2)
	expectedNeighbors = []Edge[int, int]{{ID: 1, src: 2, dest: 1, weight: 10}, {ID: 3, src: 2, dest: 3, weight: 30}}
	if !equalEdges(neighbors, expectedNeighbors) {
		t.Errorf("GetNeighbors() failed for vertex 2: expected %v, got %v", expectedNeighbors, neighbors)
	}

	// Test GetNeighbors for vertex 3
	neighbors = g.GetNeighbors(3)
	expectedNeighbors = []Edge[int, int]{{ID: 2, src: 3, dest: 1, weight: 20}, {ID: 3, src: 3, dest: 2, weight: 30}}
	if !equalEdges(neighbors, expectedNeighbors) {
		t.Errorf("GetNeighbors() failed for vertex 3: expected %v, got %v", expectedNeighbors, neighbors)
	}
}

// Helper function to check if two slices of edges are equal
func equalEdges(edges1, edges2 []Edge[int, int]) bool {
	if len(edges1) != len(edges2) {
		return false
	}
	for i := 0; i < len(edges1); i++ {
		if edges1[i] != edges2[i] {
			return false
		}
	}
	return true
}

func TestHasNeighbor(t *testing.T) {
	g := NewGraph[int, int]()

	// Add edges to the graph
	g.AddEdge(1, 2, 10)
	g.AddEdge(1, 3, 20)
	g.AddEdge(2, 3, 30)

	// Test HasNeighbor for existing neighbors
	if !g.HasNeighbor(1, 2) {
		t.Errorf("HasNeighbor() failed: expected true, got false")
	}
	if !g.HasNeighbor(1, 3) {
		t.Errorf("HasNeighbor() failed: expected true, got false")
	}
	if !g.HasNeighbor(2, 3) {
		t.Errorf("HasNeighbor() failed: expected true, got false")
	}
	if !g.HasNeighbor(3, 1) {
		t.Errorf("HasNeighbor() failed: expected true, got false")
	}
	if !g.HasNeighbor(2, 1) {
		t.Errorf("HasNeighbor() failed: expected true, got false")
	}

	// Test HasNeighbor for non-existing neighbors
	if g.HasNeighbor(1, 4) {
		t.Errorf("HasNeighbor() failed: expected false, got true")
	}
}

func TestGetEdge(t *testing.T) {
	g := NewGraph[int, int]()
	g.AddEdge(1, 2, 10)
	g.AddEdge(2, 3, 20)
	g.AddEdge(3, 4, 30)

	// Test existing edge
	expectedEdge := Edge[int, int]{ID: 1, src: 1, dest: 2, weight: 10}
	edge := g.GetEdge(1, 2)
	if edge != expectedEdge {
		t.Errorf("GetEdge() failed for existing edge: expected %v, got %v", expectedEdge, edge)
	}

	// Test non-existing edge
	edge = g.GetEdge(1, 3)
	if edge != (Edge[int, int]{}) {
		t.Errorf("GetEdge() failed for non-existing edge: expected empty edge, got %v", edge)
	}
}

func TestString(t *testing.T) {
	g := NewGraph[int, int]()

	// Add vertices and edges to the graph
	g.AddEdge(1, 2, 10)
	g.AddEdge(1, 3, 20)
	g.AddEdge(2, 3, 30)

	result := g.String()

	if !strings.Contains(result, "1: (1, 1, 2, 10) (2, 1, 3, 20)\n") || !strings.Contains(result, "2: (1, 2, 1, 10) (3, 2, 3, 30)\n") || !strings.Contains(result, "3: (2, 3, 1, 20) (3, 3, 2, 30)\n") {
		t.Errorf("String() failed and got %q", result)
	}
}

func TestCountComponents(t *testing.T) {
	g := NewGraph[int, int]()

	// Add vertices and edges to the graph
	g.AddEdge(1, 2, 10)
	g.AddEdge(2, 3, 20)
	g.AddEdge(4, 5, 30)

	expectedCount := 2
	actualCount := g.CountComponents()
	if actualCount != expectedCount {
		t.Errorf("CountComponents() failed: expected count = %d, got count = %d", expectedCount, actualCount)
	}

	// Add another component to the graph
	g.AddEdge(6, 7, 40)
	g.AddEdge(7, 8, 50)

	expectedCount = 3
	actualCount = g.CountComponents()
	if actualCount != expectedCount {
		t.Errorf("CountComponents() failed: expected count = %d, got count = %d", expectedCount, actualCount)
	}
}

func TestIsConnected(t *testing.T) {
	g := NewGraph[int, int]()

	// Add vertices and edges to the graph
	g.AddEdge(1, 2, 10)
	g.AddEdge(2, 3, 20)
	g.AddEdge(3, 4, 30)

	// Test IsConnected for a connected graph
	if !g.IsConnected() {
		t.Errorf("IsConnected() failed: expected true, got false")
	}

	// Test IsConnected for a disconnected graph
	g.AddVertex(5)
	if g.IsConnected() {
		t.Errorf("IsConnected() failed: expected false, got true")
	}
}

func TestIsCyclic(t *testing.T) {
	g := NewGraph[int, int]()

	// Add edges to create a cyclic graph
	g.AddEdge(1, 2, 10)
	g.AddEdge(2, 3, 20)
	g.AddEdge(3, 1, 30)

	// Check if the graph is cyclic
	if !g.IsCyclic() {
		t.Errorf("IsCyclic() failed: expected true, got false")
	}

	// Add edges to create an acyclic graph
	g = NewGraph[int, int]()
	g.AddEdge(1, 2, 10)
	g.AddEdge(2, 3, 20)
	g.AddEdge(3, 4, 30)

	// Check if the graph is acyclic
	if g.IsCyclic() {
		t.Errorf("IsCyclic() failed: expected false, got true")
	}
}

func TestIsCyclicUtil(t *testing.T) {
	g := NewGraph[int, int]()
	g.AddEdge(1, 2, 10)
	g.AddEdge(2, 3, 20)
	g.AddEdge(3, 1, 30)

	visited := make(map[int]bool)
	recStack := make(map[int]bool)
	edgeIDs := make(map[int]bool)

	// Test for cyclic graph
	if !g.isCyclicUtil(1, visited, recStack, edgeIDs) {
		t.Errorf("isCyclicUtil() failed: expected true, got false")
	}

	g = NewGraph[int, int]()
	g.AddEdge(1, 2, 10)
	g.AddEdge(2, 3, 20)
	g.AddEdge(3, 4, 30)

	visited = make(map[int]bool)
	recStack = make(map[int]bool)
	edgeIDs = make(map[int]bool)

	// Test for acyclic graph
	if g.isCyclicUtil(1, visited, recStack, edgeIDs) {
		t.Errorf("isCyclicUtil() failed: expected false, got true")
	}
}

func TestIsTree(t *testing.T) {
	// Create a new graph
	g := NewGraph[int, int]()

	// Add vertices and edges to the graph
	g.AddEdge(1, 2, 10)
	g.AddEdge(2, 3, 20)
	g.AddEdge(3, 4, 30)

	// Test IsTree for a connected acyclic graph
	if !g.IsTree() {
		t.Errorf("IsTree() failed for a connected acyclic graph")
	}

	// Add an edge to create a cycle
	g.AddEdge(4, 1, 40)

	// Test IsTree for a graph with a cycle
	if g.IsTree() {
		t.Errorf("IsTree() failed for a graph with a cycle")
	}

	// Remove the edge to make the graph acyclic again
	g.RemoveEdge(4, 1)

	// Remove a vertex to make the graph disconnected
	g.RemoveVertex(3)

	// Test IsTree for a disconnected graph
	if g.IsTree() {
		t.Errorf("IsTree() failed for a disconnected graph")
	}
}

func TestIsBipartite(t *testing.T) {
	g := NewGraph[int, int]()

	// Add vertices and edges to the graph
	g.AddEdge(1, 2, 10)
	g.AddEdge(1, 3, 20)
	g.AddEdge(3, 4, 40)

	// Test for a bipartite graph
	if !g.IsBipartite() {
		t.Error("IsBipartite() failed for a bipartite graph")
	}

	// Add an edge to create a cycle
	g.AddEdge(4, 1, 50)

	// Test for a non-bipartite graph with a cycle
	if g.IsBipartite() {
		t.Error("IsBipartite() failed for a non-bipartite graph with a cycle")
	}

	// Remove the edge to break the cycle
	g.RemoveEdge(4, 1)

	// Test for a non-bipartite graph without a cycle
	if !g.IsBipartite() {
		t.Error("IsBipartite() failed for a non-bipartite graph without a cycle")
	}
}

func TestIsBipartiteUtil(t *testing.T) {
	g := NewGraph[int, int]()

	// Add vertices and edges to the graph
	g.AddEdge(1, 2, 10)
	g.AddEdge(2, 3, 20)
	g.AddEdge(3, 4, 30)

	visited := make(map[int]bool)
	colors := make(map[int]bool)
	edgeIDs := map[int]bool{}

	// Test isBipartiteUtil for a bipartite graph
	result := g.isBipartiteUtil(1, visited, colors, edgeIDs)
	expectedResult := true
	if result != expectedResult {
		t.Errorf("isBipartiteUtil() failed for bipartite graph: expected %v, got %v", expectedResult, result)
	}

	visited = make(map[int]bool)
	colors = make(map[int]bool)
	edgeIDs = map[int]bool{}

	// Test isBipartiteUtil for a non-bipartite graph
	g.AddEdge(4, 2, 40)
	result = g.isBipartiteUtil(1, visited, colors, edgeIDs)
	expectedResult = false
	if result != expectedResult {
		t.Errorf("isBipartiteUtil() failed for non-bipartite graph: expected %v, got %v", expectedResult, result)
	}
}

func TestAddVertex(t *testing.T) {
	g := NewGraph[int, int]()

	// Add a vertex to the graph
	g.AddVertex(1)

	// Check if the vertex is added correctly
	expectedAdjacencyList := map[int][]Edge[int, int]{
		1: {},
	}
	if !compareAdjacencyLists(g.adjacencyList, expectedAdjacencyList) {
		t.Errorf("AddVertex() failed: expected adjacency list = %v, got %v", expectedAdjacencyList, g.adjacencyList)
	}
}
func TestGetVertices(t *testing.T) {
	g := NewGraph[int, int]()

	// Add vertices to the graph
	g.AddVertex(1)
	g.AddVertex(2)
	g.AddVertex(3)

	// Get the vertices from the graph
	vertices := g.GetVertices()

	// Check if the vertices are returned correctly
	expectedVertices := []int{1, 2, 3}
	if !equalSlices(vertices, expectedVertices) {
		t.Errorf("GetVertices() failed: expected %v, got %v", expectedVertices, vertices)
	}
}

// Helper function to check if two slices are equal
func equalSlices(a, b []int) bool {
	sort.Ints(a)
	sort.Ints(b)

	if len(a) != len(b) {
		return false
	}
	for i := 0; i < len(a); i++ {
		if a[i] != b[i] {
			return false
		}
	}
	return true
}

func TestRemoveEdge(t *testing.T) {
	g := NewGraph[int, int]()
	g.AddEdge(1, 2, 10)
	g.AddEdge(2, 3, 20)
	g.AddEdge(3, 4, 30)

	// Test removing an existing edge
	g.RemoveEdge(1, 2)
	if edges := g.GetEdges(); len(edges) != 2 {
		t.Errorf("RemoveEdge() failed: expected 2 edges, got %d", len(edges))
	}
	if neighbors := g.GetNeighbors(1); len(neighbors) != 0 {
		t.Errorf("RemoveEdge() failed: expected 0 neighbors for vertex 1, got %d", len(neighbors))
	}
	if neighbors := g.GetNeighbors(2); len(neighbors) != 1 {
		t.Errorf("RemoveEdge() failed: expected 1 neighbor for vertex 2, got %d", len(neighbors))
	}

	// Test removing a non-existing edge
	g.RemoveEdge(1, 3)
	if edges := g.GetEdges(); len(edges) != 2 {
		t.Errorf("RemoveEdge() failed: expected 2 edges, got %d", len(edges))
	}
	if neighbors := g.GetNeighbors(1); len(neighbors) != 0 {
		t.Errorf("RemoveEdge() failed: expected 0 neighbors for vertex 1, got %d", len(neighbors))
	}
	if neighbors := g.GetNeighbors(3); len(neighbors) != 2 {
		t.Errorf("RemoveEdge() failed: expected 1 neighbor for vertex 3, got %d", len(neighbors))
	}
}

func TestRemoveVertex(t *testing.T) {
	g := NewGraph[int, int]()

	// Add vertices and edges to the graph
	g.AddEdge(1, 2, 10)
	g.AddEdge(1, 3, 20)
	g.AddEdge(2, 3, 30)
	g.AddEdge(3, 4, 40)

	// Remove vertex 2
	g.RemoveVertex(2)

	// Check if the vertex is removed correctly
	expectedAdjacencyList := map[int][]Edge[int, int]{
		1: {{2, 1, 3, 20}},
		3: {{2, 3, 1, 20}, {4, 3, 4, 40}},
		4: {{4, 4, 3, 40}},
	}
	if !compareAdjacencyLists(g.adjacencyList, expectedAdjacencyList) {
		t.Errorf("RemoveVertex() failed: expected adjacency list = %v, got %v", expectedAdjacencyList, g.adjacencyList)
	}

	expectedEdges := []Edge[int, int]{
		{2, 1, 3, 20},
		{4, 3, 4, 40},
	}
	if !compareEdges(g.edges, expectedEdges) {
		t.Errorf("RemoveVertex() failed: expected edges list = %v, got %v", expectedEdges, g.edges)
	}

	expectedV := 3
	if g.v != expectedV {
		t.Errorf("RemoveVertex() failed: expected v = %d, got v = %d", expectedV, g.v)
	}

	expectedE := 2
	if g.e != expectedE {
		t.Errorf("RemoveVertex() failed: expected e = %d, got e = %d", expectedE, g.e)
	}
}

func TestGetEdges(t *testing.T) {
	g := NewGraph[int, int]()
	g.AddEdge(1, 2, 10)
	g.AddEdge(2, 3, 20)
	g.AddEdge(3, 4, 30)

	// Test GetEdges
	expectedEdges := []Edge[int, int]{
		{ID: 1, src: 1, dest: 2, weight: 10},
		{ID: 2, src: 2, dest: 3, weight: 20},
		{ID: 3, src: 3, dest: 4, weight: 30},
	}
	edges := g.GetEdges()
	if !compareEdges(edges, expectedEdges) {
		t.Errorf("GetEdges() failed: expected edges = %v, got edges = %v", expectedEdges, edges)
	}
}

func TestRemoveEdgeWithID(t *testing.T) {
	g := NewGraph[int, int]()
	g.AddEdge(1, 2, 10)
	g.AddEdge(2, 3, 20)
	g.AddEdge(3, 4, 30)

	// Test removing an existing edge
	g.RemoveEdgeWithID(1)

	// Check if the edge is removed from the list of edges
	expectedEdges := []Edge[int, int]{
		{ID: 2, src: 2, dest: 3, weight: 20},
		{ID: 3, src: 3, dest: 4, weight: 30},
	}
	if !compareEdges(g.edges, expectedEdges) {
		t.Errorf("RemoveEdgeWithID() failed: expected edges list = %v, got %v", expectedEdges, g.edges)
	}

	// Check if the edge is removed from the adjacency list
	expectedAdjacencyList := map[int][]Edge[int, int]{
		1: {},
		2: {{2, 2, 3, 20}},
		3: {{2, 3, 2, 20}, {3, 3, 4, 30}},
		4: {{3, 4, 3, 30}},
	}
	if !compareAdjacencyLists(g.adjacencyList, expectedAdjacencyList) {
		t.Errorf("RemoveEdgeWithID() failed: expected adjacency list = %v, got %v", expectedAdjacencyList, g.adjacencyList)
	}

	// Check if the edge count is updated
	expectedE := 2
	if g.e != expectedE {
		t.Errorf("RemoveEdgeWithID() failed: expected e = %d, got e = %d", expectedE, g.e)
	}

	// Test removing a non-existing edge
	g.RemoveEdgeWithID(5)

	// Check if the graph remains unchanged
	if !compareEdges(g.edges, expectedEdges) {
		t.Errorf("RemoveEdgeWithID() failed: expected edges list = %v, got %v", expectedEdges, g.edges)
	}
	if !compareAdjacencyLists(g.adjacencyList, expectedAdjacencyList) {
		t.Errorf("RemoveEdgeWithID() failed: expected adjacency list = %v, got %v", expectedAdjacencyList, g.adjacencyList)
	}
	if g.e != expectedE {
		t.Errorf("RemoveEdgeWithID() failed: expected e = %d, got e = %d", expectedE, g.e)
	}
}
func TestKargerMinCutUF(t *testing.T) {
	// Create a new graph
	g := NewGraph[int, int]()

	// Add vertices and edges to the graph
	g.AddEdge(1, 2, 10)
	g.AddEdge(1, 3, 20)
	g.AddEdge(2, 3, 30)
	g.AddEdge(3, 4, 40)
	g.AddEdge(4, 5, 50)
	g.AddEdge(4, 6, 60)
	g.AddEdge(5, 6, 70)

	// Run Karger's algorithm to find the minimum cut
	cutEdges, resultSubsets := g.kargerMinCutUF(10000)

	// Check if the number of cut edges is correct
	expectedCutEdges := 1
	if cutEdges != expectedCutEdges {
		t.Errorf("kargerMinCutUF() failed: expected cut edges = %d, got cut edges = %d", expectedCutEdges, cutEdges)
	}

	// Check if the result subsets are correct
	expectedResultSubsets := [][]int{{1, 2, 3}, {4, 5, 6}}
	if !equalSubsets(resultSubsets, expectedResultSubsets) {
		t.Errorf("kargerMinCutUF() failed: expected result subsets = %v, got result subsets = %v", expectedResultSubsets, resultSubsets)
	}
}

// Helper function to check if two subsets are equal
func equalSubsets(a, b [][]int) bool {
	if len(a) != len(b) {
		return false
	}

	for i := 0; i < len(a); i++ {
		if !equalSlices(a[i], b[i]) {
			return false
		}
	}

	return true
}

func TestBFS(t *testing.T) {
	g := NewGraph[int, int]()

	// Add vertices and edges to the graph
	g.AddEdge(1, 2, 10)
	g.AddEdge(1, 3, 20)
	g.AddEdge(2, 3, 30)
	g.AddEdge(2, 4, 40)
	g.AddEdge(3, 4, 50)

	// Define the isGoal function
	isGoal := func(vertex int) bool {
		return vertex == 4
	}

	// Perform BFS starting from vertex 1
	result := g.BFS(1, isGoal)

	// Check if the result is correct
	expectedResult := []int{1, 2, 3, 4}
	if !equalSlices(result, expectedResult) {
		t.Errorf("BFS() failed: expected %v, got %v", expectedResult, result)
	}

	// Perform BFS starting from vertex 2
	result = g.BFS(2, isGoal)

	// Check if the result is correct
	expectedResult = []int{2, 1, 3, 4}
	if !equalSlices(result, expectedResult) {
		t.Errorf("BFS() failed: expected %v, got %v", expectedResult, result)
	}

	// Perform BFS starting from vertex 3
	result = g.BFS(3, isGoal)

	// Check if the result is correct
	expectedResult = []int{3, 1, 2, 4}
	if !equalSlices(result, expectedResult) {
		t.Errorf("BFS() failed: expected %v, got %v", expectedResult, result)
	}

	// Perform BFS starting from vertex 4
	result = g.BFS(4, isGoal)

	// Check if the result is correct
	expectedResult = []int{4}
	if !equalSlices(result, expectedResult) {
		t.Errorf("BFS() failed: expected %v, got %v", expectedResult, result)
	}
}

func TestDFS(t *testing.T) {
	g := NewGraph[int, int]()
	g.AddEdge(1, 2, 10)
	g.AddEdge(2, 3, 20)
	g.AddEdge(3, 4, 30)
	g.AddEdge(4, 5, 40)
	g.AddEdge(5, 6, 50)

	// Test DFS with a goal function that returns true for vertex 6
	isGoal := func(vertex int) bool {
		return vertex == 6
	}

	result := g.DFS(1, isGoal)
	expectedResult := []int{1, 2, 3, 4, 5, 6}
	if !equalSlices(result, expectedResult) {
		t.Errorf("DFS() failed with goal function: expected %v, got %v", expectedResult, result)
	}

	// Test DFS with a goal function that returns true for vertex 3
	isGoal = func(vertex int) bool {
		return vertex == 3
	}

	result = g.DFS(1, isGoal)
	expectedResult = []int{1, 2, 3}
	if !equalSlices(result, expectedResult) {
		t.Errorf("DFS() failed with goal function: expected %v, got %v", expectedResult, result)
	}

	// Test DFS with a goal function that returns true for vertex 7 (non-existent vertex)
	isGoal = func(vertex int) bool {
		return vertex == 7
	}

	result = g.DFS(1, isGoal)
	expectedResult = []int{}
	if !equalSlices(result, expectedResult) {
		t.Errorf("DFS() failed with goal function: expected %v, got %v", expectedResult, result)
	}
}