// Ceres Solver - A fast non-linear least squares minimizer

// Copyright 2015 Google Inc. All rights reserved.

// http://ceres-solver.org/

//

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// Author: sameeragarwal@google.com (Sameer Agarwal)

#include "ceres/graph.h"

#include "gtest/gtest.h"

#include "ceres/collections_port.h"

#include "ceres/internal/scoped_ptr.h"

namespace ceres {

namespace internal {

TEST(Graph, EmptyGraph) {

  Graph<int> graph;

  EXPECT_EQ(graph.vertices().size(), 0);

}

TEST(Graph, AddVertexAndEdge) {

  Graph<int> graph;

  graph.AddVertex(0);

  graph.AddVertex(1);

  graph.AddEdge(0, 1);

  const HashSet<int>& vertices = graph.vertices();

  EXPECT_EQ(vertices.size(), 2);

  EXPECT_EQ(graph.Neighbors(0).size(), 1);

  EXPECT_EQ(graph.Neighbors(1).size(), 1);

}

TEST(Graph, AddVertexIdempotence) {

  Graph<int> graph;

  graph.AddVertex(0);

  graph.AddVertex(1);

  graph.AddEdge(0, 1);

  const HashSet<int>& vertices = graph.vertices();

  EXPECT_EQ(vertices.size(), 2);

  // Try adding the vertex again with a new weight.

  graph.AddVertex(0);

  EXPECT_EQ(vertices.size(), 2);

  // Rest of the graph remains the same.

  EXPECT_EQ(graph.Neighbors(0).size(), 1);

  EXPECT_EQ(graph.Neighbors(1).size(), 1);

}

TEST(Graph, DieOnNonExistentVertex) {

  Graph<int> graph;

  graph.AddVertex(0);

  graph.AddVertex(1);

  graph.AddEdge(0, 1);

  EXPECT_DEATH_IF_SUPPORTED(graph.Neighbors(2), "key not found");

}

TEST(WeightedGraph, EmptyGraph) {

  WeightedGraph<int> graph;

  EXPECT_EQ(graph.vertices().size(), 0);

}

TEST(WeightedGraph, AddVertexAndEdge) {

  WeightedGraph<int> graph;

  graph.AddVertex(0, 1.0);

  graph.AddVertex(1, 2.0);

  graph.AddEdge(0, 1, 0.5);

  const HashSet<int>& vertices = graph.vertices();

  EXPECT_EQ(vertices.size(), 2);

  EXPECT_EQ(graph.VertexWeight(0), 1.0);

  EXPECT_EQ(graph.VertexWeight(1), 2.0);

  EXPECT_EQ(graph.Neighbors(0).size(), 1);

  EXPECT_EQ(graph.Neighbors(1).size(), 1);

  EXPECT_EQ(graph.EdgeWeight(0, 1), 0.5);

  EXPECT_EQ(graph.EdgeWeight(1, 0), 0.5);

}

TEST(WeightedGraph, AddVertexIdempotence) {

  WeightedGraph<int> graph;

  graph.AddVertex(0, 1.0);

  graph.AddVertex(1, 2.0);

  graph.AddEdge(0, 1, 0.5);

  const HashSet<int>& vertices = graph.vertices();

  EXPECT_EQ(vertices.size(), 2);

  // Try adding the vertex again with a new weight.

  graph.AddVertex(0, 3.0);

  EXPECT_EQ(vertices.size(), 2);

  // The vertex weight is reset.

  EXPECT_EQ(graph.VertexWeight(0), 3.0);

  // Rest of the graph remains the same.

  EXPECT_EQ(graph.VertexWeight(1), 2.0);

  EXPECT_EQ(graph.Neighbors(0).size(), 1);

  EXPECT_EQ(graph.Neighbors(1).size(), 1);

  EXPECT_EQ(graph.EdgeWeight(0, 1), 0.5);

  EXPECT_EQ(graph.EdgeWeight(1, 0), 0.5);

}

TEST(WeightedGraph, DieOnNonExistentVertex) {

  WeightedGraph<int> graph;

  graph.AddVertex(0, 1.0);

  graph.AddVertex(1, 2.0);

  graph.AddEdge(0, 1, 0.5);

  EXPECT_DEATH_IF_SUPPORTED(graph.VertexWeight(2), "key not found");

  EXPECT_DEATH_IF_SUPPORTED(graph.Neighbors(2), "key not found");

}

TEST(WeightedGraph, NonExistentEdge) {

  WeightedGraph<int> graph;

  graph.AddVertex(0, 1.0);

  graph.AddVertex(1, 2.0);

  graph.AddEdge(0, 1, 0.5);

  // Default value for non-existent edges is 0.

  EXPECT_EQ(graph.EdgeWeight(2, 3), 0);

}

}  // namespace internal

}  // namespace ceres