fix: revert supporting new.target attribute (#33)

Author: sheremet-va

src/spy.ts

@@ -59,9 +59,7 @@ export function spy<A extends any[], R>(
     let type: 'ok' | 'error' = 'ok'
     if (fn.impl) {
       try {
-        result = new.target
-          ? new (fn.impl as any)(...args)
-          : fn.impl.apply(this, args)
+        result = fn.impl.apply(this, args)
         type = 'ok'
       } catch (err: any) {
         result = err

test/class.test.ts

@@ -25,40 +25,53 @@ describe('class mock', () => {
     expect(spy2.callCount).toBe(1)
   })
 
-  test('throws error, if constructor is an arrow function', () => {
-    const fnArrow = spy(() => {})
-    expect(() => new fnArrow()).toThrowError()
+  test('spy keeps instance', () => {
+    const obj = {
+      Test() {},
+    }
+    const fn = spyOn(obj, 'Test')
+    const instance = new obj.Test()
+    expect(fn.called).toBe(true)
+    expect(instance).toBeInstanceOf(obj.Test)
   })
 
-  test('respects new.target in a function', () => {
-    let target: unknown = null
-    let args: unknown[] = []
-    const fnScoped = spy(function (...fnArgs: unknown[]) {
-      target = new.target
-      args = fnArgs
+  // FIXME: https://github.com/tinylibs/tinyspy/issues/29
+  describe.todo('spying on constructor', () => {
+    test('throws error, if constructor is an arrow function', () => {
+      const fnArrow = spy(() => {})
+      expect(() => new fnArrow()).toThrowError()
     })
 
-    new fnScoped('some', 'text', 1)
-    expect(target).toBeTypeOf('function')
-    expect(args).toEqual(['some', 'text', 1])
-    expect(fnScoped.calls).toEqual([['some', 'text', 1]])
-  })
+    test('respects new.target in a function', () => {
+      let target: unknown = null
+      let args: unknown[] = []
+      const fnScoped = spy(function (...fnArgs: unknown[]) {
+        target = new.target
+        args = fnArgs
+      })
+
+      new fnScoped('some', 'text', 1)
+      expect(target).toBeTypeOf('function')
+      expect(args).toEqual(['some', 'text', 1])
+      expect(fnScoped.calls).toEqual([['some', 'text', 1]])
+    })
 
-  test('respects new.target in a class', () => {
-    let target: unknown = null
-    let args: unknown[] = []
-    const fnScoped = spy(
-      class {
-        constructor(...fnArgs: unknown[]) {
-          target = new.target
-          args = fnArgs
+    test('respects new.target in a class', () => {
+      let target: unknown = null
+      let args: unknown[] = []
+      const fnScoped = spy(
+        class {
+          constructor(...fnArgs: unknown[]) {
+            target = new.target
+            args = fnArgs
+          }
         }
-      }
-    )
+      )
 
-    new fnScoped('some', 'text', 1)
-    expect(target).toBeTypeOf('function')
-    expect(args).toEqual(['some', 'text', 1])
-    expect(fnScoped.calls).toEqual([['some', 'text', 1]])
+      new fnScoped('some', 'text', 1)
+      expect(target).toBeTypeOf('function')
+      expect(args).toEqual(['some', 'text', 1])
+      expect(fnScoped.calls).toEqual([['some', 'text', 1]])
+    })
   })
 })