[test](function) Add FE unit tests for ST_NumGeometries, ST_NumPoints, ST_Geometries functions

Author: yixuanyxzhu

fe/fe-core/src/test/java/org/apache/doris/nereids/trees/expressions/functions/scalar/StGeoComponentFunctionsTest.java

@@ -0,0 +1,135 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package org.apache.doris.nereids.trees.expressions.functions.scalar;
+
+import org.apache.doris.catalog.FunctionSignature;
+import org.apache.doris.nereids.trees.expressions.Expression;
+import org.apache.doris.nereids.trees.expressions.literal.VarcharLiteral;
+import org.apache.doris.nereids.types.ArrayType;
+import org.apache.doris.nereids.types.BigIntType;
+import org.apache.doris.nereids.types.VarcharType;
+
+import com.google.common.collect.ImmutableList;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+/**
+ * Unit tests for ST_NumGeometries, ST_NumPoints, and ST_Geometries scalar functions.
+ */
+public class StGeoComponentFunctionsTest {
+
+    @Test
+    public void testStNumGeometriesBasicProperties() {
+        Expression arg = new VarcharLiteral("test");
+        StNumGeometries func = new StNumGeometries(arg);
+
+        Assertions.assertEquals("st_numgeometries", func.getName());
+        Assertions.assertEquals(1, func.arity());
+        Assertions.assertTrue(func.nullable());
+
+        List<FunctionSignature> signatures = func.getSignatures();
+        Assertions.assertEquals(1, signatures.size());
+        Assertions.assertEquals(BigIntType.INSTANCE, signatures.get(0).returnType);
+        Assertions.assertEquals(VarcharType.SYSTEM_DEFAULT, signatures.get(0).getArgType(0));
+    }
+
+    @Test
+    public void testStNumGeometriesWithChildren() {
+        Expression arg = new VarcharLiteral("test");
+        StNumGeometries func = new StNumGeometries(arg);
+
+        Expression newArg = new VarcharLiteral("new_test");
+        StNumGeometries newFunc = func.withChildren(ImmutableList.of(newArg));
+
+        Assertions.assertNotSame(func, newFunc);
+        Assertions.assertEquals("st_numgeometries", newFunc.getName());
+        Assertions.assertEquals(1, newFunc.arity());
+    }
+
+    @Test
+    public void testStNumPointsBasicProperties() {
+        Expression arg = new VarcharLiteral("test");
+        StNumPoints func = new StNumPoints(arg);
+
+        Assertions.assertEquals("st_numpoints", func.getName());
+        Assertions.assertEquals(1, func.arity());
+        Assertions.assertTrue(func.nullable());
+
+        List<FunctionSignature> signatures = func.getSignatures();
+        Assertions.assertEquals(1, signatures.size());
+        Assertions.assertEquals(BigIntType.INSTANCE, signatures.get(0).returnType);
+        Assertions.assertEquals(VarcharType.SYSTEM_DEFAULT, signatures.get(0).getArgType(0));
+    }
+
+    @Test
+    public void testStNumPointsWithChildren() {
+        Expression arg = new VarcharLiteral("test");
+        StNumPoints func = new StNumPoints(arg);
+
+        Expression newArg = new VarcharLiteral("new_test");
+        StNumPoints newFunc = func.withChildren(ImmutableList.of(newArg));
+
+        Assertions.assertNotSame(func, newFunc);
+        Assertions.assertEquals("st_numpoints", newFunc.getName());
+        Assertions.assertEquals(1, newFunc.arity());
+    }
+
+    @Test
+    public void testStGeometriesBasicProperties() {
+        Expression arg = new VarcharLiteral("test");
+        StGeometries func = new StGeometries(arg);
+
+        Assertions.assertEquals("st_geometries", func.getName());
+        Assertions.assertEquals(1, func.arity());
+        Assertions.assertTrue(func.nullable());
+
+        List<FunctionSignature> signatures = func.getSignatures();
+        Assertions.assertEquals(1, signatures.size());
+        Assertions.assertTrue(signatures.get(0).returnType instanceof ArrayType);
+        Assertions.assertEquals(VarcharType.SYSTEM_DEFAULT, signatures.get(0).getArgType(0));
+    }
+
+    @Test
+    public void testStGeometriesWithChildren() {
+        Expression arg = new VarcharLiteral("test");
+        StGeometries func = new StGeometries(arg);
+
+        Expression newArg = new VarcharLiteral("new_test");
+        StGeometries newFunc = func.withChildren(ImmutableList.of(newArg));
+
+        Assertions.assertNotSame(func, newFunc);
+        Assertions.assertEquals("st_geometries", newFunc.getName());
+        Assertions.assertEquals(1, newFunc.arity());
+    }
+
+    @Test
+    public void testStGeometriesReturnType() {
+        Expression arg = new VarcharLiteral("test");
+        StGeometries func = new StGeometries(arg);
+
+        List<FunctionSignature> signatures = func.getSignatures();
+        FunctionSignature sig = signatures.get(0);
+
+        // Return type should be Array<Varchar>
+        Assertions.assertTrue(sig.returnType instanceof ArrayType);
+        ArrayType arrayType = (ArrayType) sig.returnType;
+        Assertions.assertTrue(arrayType.getItemType() instanceof VarcharType);
+    }
+}