test(object/toMerged): add test cases for replacing non-plain-object with plain object (toss#1499)

Author: sukvvon

src/object/toMerged.spec.ts

@@ -165,4 +165,22 @@ describe('toMerged', () => {
     expect(result).toEqual({ a: { b: { c: [2], d: 3 }, e: [4] } });
     expect(target).toEqual({ a: { b: { c: [1] } } });
   });
+
+  it('should replace non-plain-object target value with plain object from source', () => {
+    const target = { a: 'string', b: 123, c: true };
+    const source = { a: { x: 1 }, b: { y: 2 }, c: { z: 3 } };
+    const result = toMerged(target, source);
+
+    expect(result).toEqual({ a: { x: 1 }, b: { y: 2 }, c: { z: 3 } });
+    expect(target).toEqual({ a: 'string', b: 123, c: true });
+  });
+
+  it('should handle nested case where non-plain-object is replaced with plain object', () => {
+    const target = { a: { b: null, c: undefined, d: 'text' } };
+    const source = { a: { b: { x: 1 }, c: { y: 2 }, d: { z: 3 } } };
+    const result = toMerged(target, source);
+
+    expect(result).toEqual({ a: { b: { x: 1 }, c: { y: 2 }, d: { z: 3 } } });
+    expect(target).toEqual({ a: { b: null, c: undefined, d: 'text' } });
+  });
 });