test: 💍 add test for topdown matcher, for only root node cases

core/src/test/kotlin/matchers/TopDownMatcherOnlyRootTest.kt

@@ -0,0 +1,110 @@
+package matchers
+
+import kotlinx.coroutines.runBlocking
+import org.junit.jupiter.api.parallel.Execution
+import org.junit.jupiter.api.parallel.ExecutionMode
+import tw.xcc.gumtree.helper.gumTree
+import tw.xcc.gumtree.matchers.GreedyTopDownMatcher
+import tw.xcc.gumtree.model.MappingStorage
+import kotlin.test.BeforeTest
+import kotlin.test.Test
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+@Execution(ExecutionMode.CONCURRENT)
+internal class TopDownMatcherOnlyRootTest {
+    private lateinit var topDownMatcher: GreedyTopDownMatcher
+    private lateinit var storage: MappingStorage
+
+    @BeforeTest
+    fun setUp() {
+        topDownMatcher = GreedyTopDownMatcher()
+        storage = MappingStorage()
+    }
+
+    @Test
+    fun `test match with same root node on both side`() {
+        // Given
+        val tree1 = gumTree("root", "label")
+        val tree2 = gumTree("root", "label")
+
+        runBlocking {
+            // When
+            topDownMatcher.match(tree1, tree2, storage)
+
+            // Then
+            // The default minimum height is 1; the root node should not be matched,
+            // since they are also the leaf node.
+            assertFalse(storage.has(tree1 to tree2))
+        }
+    }
+
+    @Test
+    fun `test match with same root node on both side with minimum height 0`() {
+        // Given
+        val tree1 = gumTree("root", "label")
+        val tree2 = gumTree("root", "label")
+        topDownMatcher = GreedyTopDownMatcher(0)
+
+        runBlocking {
+            // When
+            topDownMatcher.match(tree1, tree2, storage)
+
+            // Then
+            // The minimum height is 0; the root node should be matched.
+            assertTrue(storage.has(tree1 to tree2))
+        }
+    }
+
+    @Test
+    fun `test match with different root node on both side`() {
+        // Given
+        val tree1 = gumTree("root1", "label")
+        val tree2 = gumTree("root2", "label")
+
+        runBlocking {
+            // When
+            topDownMatcher.match(tree1, tree2, storage)
+
+            // Then
+            // The default minimum height is 1; the root node should not be matched.
+            assertFalse(storage.has(tree1 to tree2))
+        }
+    }
+
+    @Test
+    fun `test match with different root node on both side with minimum height 0`() {
+        // Given
+        val tree1 = gumTree("root1", "label")
+        val tree2 = gumTree("root2", "label")
+        topDownMatcher = GreedyTopDownMatcher(0)
+
+        runBlocking {
+            // When
+            topDownMatcher.match(tree1, tree2, storage)
+
+            // Then
+            // The minimum height is 0; the root node should not be matched.
+            // Because they have different grammar-type
+            assertFalse(storage.has(tree1 to tree2))
+        }
+    }
+
+    @Test
+    fun `test match with different root node on both side with minimum height 0 and different label`() {
+        // Given
+        val tree1 = gumTree("root", "label-1")
+        val tree2 = gumTree("root", "label-2")
+        topDownMatcher = GreedyTopDownMatcher(0)
+
+        runBlocking {
+            // When
+            topDownMatcher.match(tree1, tree2, storage)
+
+            // Then
+            // The minimum height is 0; the root node should not be matched.
+            // Because they have different label
+            assertFalse(storage.has(tree1 to tree2))
+        }
+    }
+}