Checkpoint

tests/prolog/builtins/UnificationTest.kt

@@ -0,0 +1,52 @@
+package prolog.builtins
+
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.Test
+import prolog.ast.terms.Atom
+import prolog.ast.terms.Integer
+import prolog.ast.terms.Variable
+
+class UnificationTest {
+    /**
+     * ?- X == a.
+     * false.
+     */
+    @Test
+    fun equivalent_variable_and_atom() {
+        val variable = Variable("X")
+        val atom = Atom("a")
+
+        val result = Equivalent(variable, atom).prove(emptyMap())
+
+        assertFalse(result.any(), "Variable and atom should not be equivalent")
+    }
+
+    /**
+     * ?- a == a.
+     * true.
+     */
+    @Test
+    fun equivalent_atom_and_atom() {
+        val atom1 = Atom("a")
+        val atom2 = Atom("a")
+
+        val result = Equivalent(atom1, atom2).prove(emptyMap())
+
+        assertTrue(result.any(), "Identical atoms should be equivalent")
+        assertEquals(0, result.first().size, "No substitutions should be made")
+    }
+
+    /**
+     * ?- 1 + 2 == 3.
+     * false.
+     */
+    @Test
+    fun simple_addition_equivalence() {
+        val addition = Add(Integer(1), Integer(2))
+        val solution = Integer(3)
+
+        val result = Equivalent(addition, solution).prove(emptyMap())
+
+        assertFalse(result.any(), "Addition should be equivalent")
+    }
+}