basic tests for union-find data structure

.gitignore

@@ -30,3 +30,6 @@
 *.exe
 *.out
 *.app
+
+# ignore the build folder contents from git
+build/

CMakeLists.txt

@@ -60,6 +60,7 @@ add_executable(test_exe test/main.cpp
 						test/PartitionTest.cpp
 						test/DialTest.cpp
 						test/GraphSlicingTest.cpp
+						test/UnionFindTest.cpp
 				)
 target_include_directories(test_exe PUBLIC
 						  "${PROJECT_SOURCE_DIR}/include"

test/UnionFindTest.cpp

@@ -0,0 +1,54 @@
+#include "gtest/gtest.h"
+#include "CXXGraph.hpp"
+
+TEST(UnionFindTest, test_1)
+{
+    CXXGRAPH::Node<int> node0(0, 0);
+    CXXGRAPH::Node<int> node1(1, 1);
+    CXXGRAPH::Node<int> node2(2, 2);
+    CXXGRAPH::Node<int> node3(3, 3);
+
+    /*
+            0
+           1 2
+          3
+    */
+    CXXGRAPH::UndirectedWeightedEdge<int> edge1(0, node0, node1, 5);
+    CXXGRAPH::UndirectedWeightedEdge<int> edge2(1, node0, node2, 10);
+    CXXGRAPH::UndirectedWeightedEdge<int> edge3(2, node1, node3, 5);
+
+    std::list<const CXXGRAPH::Edge<int> *> edgeSet;
+    edgeSet.push_back(&edge1);
+
+    CXXGRAPH::Graph<int> graph(edgeSet);
+
+    // every element is a subset of itself
+    CXXGRAPH::Subset subset[4] = {{0, 0}, {1, 0}, {2, 0}, {3, 0}};
+    auto res = graph.setFind(subset, node0.getId());
+    ASSERT_EQ(res, 0);
+    res = graph.setFind(subset, node1.getId());
+    ASSERT_EQ(res, 1);
+    res = graph.setFind(subset, node2.getId());
+    ASSERT_EQ(res, 2);
+
+    // element 1 & 2 are subset of 0
+    // element 3 is subset of 1
+    CXXGRAPH::Subset subset1[4] = {{0, 0}, {0, 0}, {0, 0}, {1, 0}};
+    auto res1 = graph.setFind(subset1, node0.getId());
+    ASSERT_EQ(res1, 0);
+    res = graph.setFind(subset1, node3.getId());
+    ASSERT_EQ(res1, 0);
+    res = graph.setFind(subset1, node2.getId());
+    ASSERT_EQ(res1, 0);
+
+    // union of (node 1 & node3)  should increase node0 rank by 1
+    CXXGRAPH::Subset subset2[4] = {{0, 0}, {0, 0}, {0, 0}, {1, 0}};
+    graph.setUnion(subset2, node1.getId(), node3.getId());
+    ASSERT_EQ(subset2[0].rank, 1);
+    ASSERT_EQ(subset2[3].parent, 0);
+
+    // rank shouldn't increase since both have the same parent
+    graph.setUnion(subset2, node2.getId(), node3.getId());
+    ASSERT_EQ(subset2[0].rank, 1);
+    ASSERT_EQ(subset2[3].parent, 0);
+}