add more unit tests

tests/reflect.spec.ts

@@ -143,6 +143,9 @@ describe('Reflector', () => {
     const b = new B();
     const noop = new Noop();
     expect(reflector.get('foo', A)).toEqual('first');
+    expect(reflector.get('foo', a)).toEqual('first');
+    expect(reflector.get('foo', B)).toEqual('first');
+    expect(reflector.get('foo', b)).toEqual('first');
     expect(reflector.get('foo', a, 'b')).toEqual('second');
     expect(reflector.get('foo', A, 'b')).toEqual('second');
     expect(reflector.get('foo', B, 'b')).toEqual('third');
@@ -154,4 +157,24 @@ describe('Reflector', () => {
     expect(reflector.get('foo', Object, 'b')).toBeUndefined();
     expect(reflector.get('foo', Function, 'b')).toBeUndefined();
   });
+
+  it('should inherit the keys on inherited class', () => {
+    class A {
+      @Metadata.set('foo', 'first', 'keys')
+      public a: string;
+    }
+
+    class B extends A {
+      @Metadata.set('foo', 'second', 'keys')
+      public b: string;
+    }
+
+    const a = new A();
+    const b = new B();
+
+    expect(reflector.get('keys', A)).toEqual(['a', 'b']);
+    expect(reflector.get('keys', a)).toEqual(['a', 'b']);
+    expect(reflector.get('keys', B)).toEqual(['a', 'b']);
+    expect(reflector.get('keys', b)).toEqual(['a', 'b']);
+  });
 });