[cleanup] Misc

Closes #7030, closes #6967

3 files changed, 207 insertions, 367 deletions

diff --git a/test/helper.py b/test/helper.py
index 0b90660ff..539b2f618 100644
--- a/test/helper.py
+++ b/test/helper.py
@@ -194,8 +194,8 @@ def sanitize_got_info_dict(got_dict):
         'formats', 'thumbnails', 'subtitles', 'automatic_captions', 'comments', 'entries',
 
         # Auto-generated
-        'autonumber', 'playlist', 'format_index', 'video_ext', 'audio_ext', 'duration_string', 'epoch',
-        'fulltitle', 'extractor', 'extractor_key', 'filepath', 'infojson_filename', 'original_url', 'n_entries',
+        'autonumber', 'playlist', 'format_index', 'video_ext', 'audio_ext', 'duration_string', 'epoch', 'n_entries',
+        'fulltitle', 'extractor', 'extractor_key', 'filename', 'filepath', 'infojson_filename', 'original_url',
 
         # Only live_status needs to be checked
         'is_live', 'was_live',
diff --git a/test/test_YoutubeDL.py b/test/test_YoutubeDL.py
index 3c26bd7c6..477fd220e 100644
--- a/test/test_YoutubeDL.py
+++ b/test/test_YoutubeDL.py
@@ -757,7 +757,7 @@ class TestYoutubeDL(unittest.TestCase):
         test('%(id)r %(height)r', "'1234' 1080")
         test('%(ext)s-%(ext|def)d', 'mp4-def')
         test('%(width|0)04d', '0000')
-        test('a%(width|)d', 'a', outtmpl_na_placeholder='none')
+        test('a%(width|b)d', 'ab', outtmpl_na_placeholder='none')
 
         FORMATS = self.outtmpl_info['formats']
         sanitize = lambda x: x.replace(':', '：').replace('"', "＂").replace('\n', ' ')
@@ -871,12 +871,12 @@ class TestYoutubeDL(unittest.TestCase):
 
         class SimplePP(PostProcessor):
             def run(self, info):
-                with open(audiofile, 'wt') as f:
+                with open(audiofile, 'w') as f:
                     f.write('EXAMPLE')
                 return [info['filepath']], info
 
         def run_pp(params, PP):
-            with open(filename, 'wt') as f:
+            with open(filename, 'w') as f:
                 f.write('EXAMPLE')
             ydl = YoutubeDL(params)
             ydl.add_post_processor(PP())
@@ -895,7 +895,7 @@ class TestYoutubeDL(unittest.TestCase):
 
         class ModifierPP(PostProcessor):
             def run(self, info):
-                with open(info['filepath'], 'wt') as f:
+                with open(info['filepath'], 'w') as f:
                     f.write('MODIFIED')
                 return [], info
 
diff --git a/test/test_jsinterp.py b/test/test_jsinterp.py
index 26711502a..444909b84 100644
--- a/test/test_jsinterp.py
+++ b/test/test_jsinterp.py
@@ -14,462 +14,302 @@ from yt_dlp.jsinterp import JS_Undefined, JSInterpreter
 
 
 class TestJSInterpreter(unittest.TestCase):
-    def test_basic(self):
-        jsi = JSInterpreter('function x(){;}')
-        self.assertEqual(jsi.call_function('x'), None)
-
-        jsi = JSInterpreter('function x3(){return 42;}')
-        self.assertEqual(jsi.call_function('x3'), 42)
+    def _test(self, code, ret, func='f', args=()):
+        self.assertEqual(JSInterpreter(code).call_function(func, *args), ret)
 
-        jsi = JSInterpreter('function x3(){42}')
-        self.assertEqual(jsi.call_function('x3'), None)
+    def test_basic(self):
+        jsi = JSInterpreter('function f(){;}')
+        self.assertEqual(repr(jsi.extract_function('f')), 'F<f>')
+        self.assertEqual(jsi.call_function('f'), None)
 
-        jsi = JSInterpreter('var x5 = function(){return 42;}')
-        self.assertEqual(jsi.call_function('x5'), 42)
+        self._test('function f(){return 42;}', 42)
+        self._test('function f(){42}', None)
+        self._test('var f = function(){return 42;}', 42)
 
     def test_calc(self):
-        jsi = JSInterpreter('function x4(a){return 2*a+1;}')
-        self.assertEqual(jsi.call_function('x4', 3), 7)
+        self._test('function f(a){return 2*a+1;}', 7, args=[3])
 
     def test_empty_return(self):
-        jsi = JSInterpreter('function f(){return; y()}')
-        self.assertEqual(jsi.call_function('f'), None)
+        self._test('function f(){return; y()}', None)
 
     def test_morespace(self):
-        jsi = JSInterpreter('function x (a) { return 2 * a + 1 ; }')
-        self.assertEqual(jsi.call_function('x', 3), 7)
-
-        jsi = JSInterpreter('function f () { x =  2  ; return x; }')
-        self.assertEqual(jsi.call_function('f'), 2)
+        self._test('function f (a) { return 2 * a + 1 ; }', 7, args=[3])
+        self._test('function f () { x =  2  ; return x; }', 2)
 
     def test_strange_chars(self):
-        jsi = JSInterpreter('function $_xY1 ($_axY1) { var $_axY2 = $_axY1 + 1; return $_axY2; }')
-        self.assertEqual(jsi.call_function('$_xY1', 20), 21)
+        self._test('function $_xY1 ($_axY1) { var $_axY2 = $_axY1 + 1; return $_axY2; }',
+                   21, args=[20], func='$_xY1')
 
     def test_operators(self):
-        jsi = JSInterpreter('function f(){return 1 << 5;}')
-        self.assertEqual(jsi.call_function('f'), 32)
-
-        jsi = JSInterpreter('function f(){return 2 ** 5}')
-        self.assertEqual(jsi.call_function('f'), 32)
-
-        jsi = JSInterpreter('function f(){return 19 & 21;}')
-        self.assertEqual(jsi.call_function('f'), 17)
-
-        jsi = JSInterpreter('function f(){return 11 >> 2;}')
-        self.assertEqual(jsi.call_function('f'), 2)
-
-        jsi = JSInterpreter('function f(){return []? 2+3: 4;}')
-        self.assertEqual(jsi.call_function('f'), 5)
-
-        jsi = JSInterpreter('function f(){return 1 == 2}')
-        self.assertEqual(jsi.call_function('f'), False)
-
-        jsi = JSInterpreter('function f(){return 0 && 1 || 2;}')
-        self.assertEqual(jsi.call_function('f'), 2)
-
-        jsi = JSInterpreter('function f(){return 0 ?? 42;}')
-        self.assertEqual(jsi.call_function('f'), 0)
-
-        jsi = JSInterpreter('function f(){return "life, the universe and everything" < 42;}')
-        self.assertFalse(jsi.call_function('f'))
+        self._test('function f(){return 1 << 5;}', 32)
+        self._test('function f(){return 2 ** 5}', 32)
+        self._test('function f(){return 19 & 21;}', 17)
+        self._test('function f(){return 11 >> 2;}', 2)
+        self._test('function f(){return []? 2+3: 4;}', 5)
+        self._test('function f(){return 1 == 2}', False)
+        self._test('function f(){return 0 && 1 || 2;}', 2)
+        self._test('function f(){return 0 ?? 42;}', 0)
+        self._test('function f(){return "life, the universe and everything" < 42;}', False)
 
     def test_array_access(self):
-        jsi = JSInterpreter('function f(){var x = [1,2,3]; x[0] = 4; x[0] = 5; x[2.0] = 7; return x;}')
-        self.assertEqual(jsi.call_function('f'), [5, 2, 7])
+        self._test('function f(){var x = [1,2,3]; x[0] = 4; x[0] = 5; x[2.0] = 7; return x;}', [5, 2, 7])
 
     def test_parens(self):
-        jsi = JSInterpreter('function f(){return (1) + (2) * ((( (( (((((3)))))) )) ));}')
-        self.assertEqual(jsi.call_function('f'), 7)
-
-        jsi = JSInterpreter('function f(){return (1 + 2) * 3;}')
-        self.assertEqual(jsi.call_function('f'), 9)
+        self._test('function f(){return (1) + (2) * ((( (( (((((3)))))) )) ));}', 7)
+        self._test('function f(){return (1 + 2) * 3;}', 9)
 
     def test_quotes(self):
-        jsi = JSInterpreter(R'function f(){return "a\"\\("}')
-        self.assertEqual(jsi.call_function('f'), R'a"\(')
+        self._test(R'function f(){return "a\"\\("}', R'a"\(')
 
     def test_assignments(self):
-        jsi = JSInterpreter('function f(){var x = 20; x = 30 + 1; return x;}')
-        self.assertEqual(jsi.call_function('f'), 31)
-
-        jsi = JSInterpreter('function f(){var x = 20; x += 30 + 1; return x;}')
-        self.assertEqual(jsi.call_function('f'), 51)
-
-        jsi = JSInterpreter('function f(){var x = 20; x -= 30 + 1; return x;}')
-        self.assertEqual(jsi.call_function('f'), -11)
+        self._test('function f(){var x = 20; x = 30 + 1; return x;}', 31)
+        self._test('function f(){var x = 20; x += 30 + 1; return x;}', 51)
+        self._test('function f(){var x = 20; x -= 30 + 1; return x;}', -11)
 
     def test_comments(self):
         'Skipping: Not yet fully implemented'
         return
-        jsi = JSInterpreter('''
-        function x() {
-            var x = /* 1 + */ 2;
-            var y = /* 30
-            * 40 */ 50;
-            return x + y;
-        }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 52)
-
-        jsi = JSInterpreter('''
-        function f() {
-            var x = "/*";
-            var y = 1 /* comment */ + 2;
-            return y;
-        }
-        ''')
-        self.assertEqual(jsi.call_function('f'), 3)
+        self._test('''
+            function f() {
+                var x = /* 1 + */ 2;
+                var y = /* 30
+                * 40 */ 50;
+                return x + y;
+            }
+        ''', 52)
+
+        self._test('''
+            function f() {
+                var x = "/*";
+                var y = 1 /* comment */ + 2;
+                return y;
+            }
+        ''', 3)
 
     def test_precedence(self):
-        jsi = JSInterpreter('''
-        function x() {
-            var a = [10, 20, 30, 40, 50];
-            var b = 6;
-            a[0]=a[b%a.length];
-            return a;
-        }''')
-        self.assertEqual(jsi.call_function('x'), [20, 20, 30, 40, 50])
+        self._test('''
+            function f() {
+                var a = [10, 20, 30, 40, 50];
+                var b = 6;
+                a[0]=a[b%a.length];
+                return a;
+            }
+        ''', [20, 20, 30, 40, 50])
 
     def test_builtins(self):
-        jsi = JSInterpreter('''
-        function x() { return NaN }
-        ''')
-        self.assertTrue(math.isnan(jsi.call_function('x')))
+        jsi = JSInterpreter('function f() { return NaN }')
+        self.assertTrue(math.isnan(jsi.call_function('f')))
 
-        jsi = JSInterpreter('''
-        function x() { return new Date('Wednesday 31 December 1969 18:01:26 MDT') - 0; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 86000)
-        jsi = JSInterpreter('''
-        function x(dt) { return new Date(dt) - 0; }
-        ''')
-        self.assertEqual(jsi.call_function('x', 'Wednesday 31 December 1969 18:01:26 MDT'), 86000)
+        self._test('function f() { return new Date("Wednesday 31 December 1969 18:01:26 MDT") - 0; }',
+                   86000)
+        self._test('function f(dt) { return new Date(dt) - 0; }',
+                   86000, args=['Wednesday 31 December 1969 18:01:26 MDT'])
 
     def test_call(self):
         jsi = JSInterpreter('''
-        function x() { return 2; }
-        function y(a) { return x() + (a?a:0); }
-        function z() { return y(3); }
+            function x() { return 2; }
+            function y(a) { return x() + (a?a:0); }
+            function z() { return y(3); }
         ''')
         self.assertEqual(jsi.call_function('z'), 5)
         self.assertEqual(jsi.call_function('y'), 2)
 
     def test_if(self):
-        jsi = JSInterpreter('''
-        function x() {
-            let a = 9;
-            if (0==0) {a++}
-            return a
-        }''')
-        self.assertEqual(jsi.call_function('x'), 10)
-
-        jsi = JSInterpreter('''
-        function x() {
-            if (0==0) {return 10}
-        }''')
-        self.assertEqual(jsi.call_function('x'), 10)
-
-        jsi = JSInterpreter('''
-        function x() {
-            if (0!=0) {return 1}
-            else {return 10}
-        }''')
-        self.assertEqual(jsi.call_function('x'), 10)
+        self._test('''
+            function f() {
+                let a = 9;
+                if (0==0) {a++}
+                return a
+            }
+        ''', 10)
+
+        self._test('''
+            function f() {
+                if (0==0) {return 10}
+            }
+        ''', 10)
+
+        self._test('''
+            function f() {
+                if (0!=0) {return 1}
+                else {return 10}
+            }
+        ''', 10)
 
         """  # Unsupported
-        jsi = JSInterpreter('''
-        function x() {
-            if (0!=0) {return 1}
-            else if (1==0) {return 2}
-            else {return 10}
-        }''')
-        self.assertEqual(jsi.call_function('x'), 10)
+        self._test('''
+            function f() {
+                if (0!=0) {return 1}
+                else if (1==0) {return 2}
+                else {return 10}
+            }
+        ''', 10)
         """
 
     def test_for_loop(self):
-        jsi = JSInterpreter('''
-        function x() { a=0; for (i=0; i-10; i++) {a++} return a }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 10)
+        self._test('function f() { a=0; for (i=0; i-10; i++) {a++} return a }', 10)
 
     def test_switch(self):
         jsi = JSInterpreter('''
-        function x(f) { switch(f){
-            case 1:f+=1;
-            case 2:f+=2;
-            case 3:f+=3;break;
-            case 4:f+=4;
-            default:f=0;
-        } return f }
+            function f(x) { switch(x){
+                case 1:x+=1;
+                case 2:x+=2;
+                case 3:x+=3;break;
+                case 4:x+=4;
+                default:x=0;
+            } return x }
         ''')
-        self.assertEqual(jsi.call_function('x', 1), 7)
-        self.assertEqual(jsi.call_function('x', 3), 6)
-        self.assertEqual(jsi.call_function('x', 5), 0)
+        self.assertEqual(jsi.call_function('f', 1), 7)
+        self.assertEqual(jsi.call_function('f', 3), 6)
+        self.assertEqual(jsi.call_function('f', 5), 0)
 
     def test_switch_default(self):
         jsi = JSInterpreter('''
-        function x(f) { switch(f){
-            case 2: f+=2;
-            default: f-=1;
-            case 5:
-            case 6: f+=6;
-            case 0: break;
-            case 1: f+=1;
-        } return f }
+            function f(x) { switch(x){
+                case 2: x+=2;
+                default: x-=1;
+                case 5:
+                case 6: x+=6;
+                case 0: break;
+                case 1: x+=1;
+            } return x }
         ''')
-        self.assertEqual(jsi.call_function('x', 1), 2)
-        self.assertEqual(jsi.call_function('x', 5), 11)
-        self.assertEqual(jsi.call_function('x', 9), 14)
+        self.assertEqual(jsi.call_function('f', 1), 2)
+        self.assertEqual(jsi.call_function('f', 5), 11)
+        self.assertEqual(jsi.call_function('f', 9), 14)
 
     def test_try(self):
-        jsi = JSInterpreter('''
-        function x() { try{return 10} catch(e){return 5} }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 10)
+        self._test('function f() { try{return 10} catch(e){return 5} }', 10)
 
     def test_catch(self):
-        jsi = JSInterpreter('''
-        function x() { try{throw 10} catch(e){return 5} }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 5)
+        self._test('function f() { try{throw 10} catch(e){return 5} }', 5)
 
     def test_finally(self):
-        jsi = JSInterpreter('''
-        function x() { try{throw 10} finally {return 42} }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 42)
-        jsi = JSInterpreter('''
-        function x() { try{throw 10} catch(e){return 5} finally {return 42} }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 42)
+        self._test('function f() { try{throw 10} finally {return 42} }', 42)
+        self._test('function f() { try{throw 10} catch(e){return 5} finally {return 42} }', 42)
 
     def test_nested_try(self):
-        jsi = JSInterpreter('''
-        function x() {try {
-            try{throw 10} finally {throw 42}
-            } catch(e){return 5} }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 5)
+        self._test('''
+            function f() {try {
+                try{throw 10} finally {throw 42}
+                } catch(e){return 5} }
+        ''', 5)
 
     def test_for_loop_continue(self):
-        jsi = JSInterpreter('''
-        function x() { a=0; for (i=0; i-10; i++) { continue; a++ } return a }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 0)
+        self._test('function f() { a=0; for (i=0; i-10; i++) { continue; a++ } return a }', 0)
 
     def test_for_loop_break(self):
-        jsi = JSInterpreter('''
-        function x() { a=0; for (i=0; i-10; i++) { break; a++ } return a }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 0)
+        self._test('function f() { a=0; for (i=0; i-10; i++) { break; a++ } return a }', 0)
 
     def test_for_loop_try(self):
-        jsi = JSInterpreter('''
-        function x() {
-            for (i=0; i-10; i++) { try { if (i == 5) throw i} catch {return 10} finally {break} };
-            return 42 }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 42)
+        self._test('''
+            function f() {
+                for (i=0; i-10; i++) { try { if (i == 5) throw i} catch {return 10} finally {break} };
+                return 42 }
+        ''', 42)
 
     def test_literal_list(self):
-        jsi = JSInterpreter('''
-        function x() { return [1, 2, "asdf", [5, 6, 7]][3] }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [5, 6, 7])
+        self._test('function f() { return [1, 2, "asdf", [5, 6, 7]][3] }', [5, 6, 7])
 
     def test_comma(self):
-        jsi = JSInterpreter('''
-        function x() { a=5; a -= 1, a+=3; return a }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 7)
-
-        jsi = JSInterpreter('''
-        function x() { a=5; return (a -= 1, a+=3, a); }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 7)
-
-        jsi = JSInterpreter('''
-        function x() { return (l=[0,1,2,3], function(a, b){return a+b})((l[1], l[2]), l[3]) }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 5)
+        self._test('function f() { a=5; a -= 1, a+=3; return a }', 7)
+        self._test('function f() { a=5; return (a -= 1, a+=3, a); }', 7)
+        self._test('function f() { return (l=[0,1,2,3], function(a, b){return a+b})((l[1], l[2]), l[3]) }', 5)
 
     def test_void(self):
-        jsi = JSInterpreter('''
-        function x() { return void 42; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), None)
+        self._test('function f() { return void 42; }', None)
 
     def test_return_function(self):
         jsi = JSInterpreter('''
-        function x() { return [1, function(){return 1}][1] }
+            function f() { return [1, function(){return 1}][1] }
         ''')
-        self.assertEqual(jsi.call_function('x')([]), 1)
+        self.assertEqual(jsi.call_function('f')([]), 1)
 
     def test_null(self):
-        jsi = JSInterpreter('''
-        function x() { return null; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), None)
-
-        jsi = JSInterpreter('''
-        function x() { return [null > 0, null < 0, null == 0, null === 0]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [False, False, False, False])
-
-        jsi = JSInterpreter('''
-        function x() { return [null >= 0, null <= 0]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [True, True])
+        self._test('function f() { return null; }', None)
+        self._test('function f() { return [null > 0, null < 0, null == 0, null === 0]; }',
+                   [False, False, False, False])
+        self._test('function f() { return [null >= 0, null <= 0]; }', [True, True])
 
     def test_undefined(self):
-        jsi = JSInterpreter('''
-        function x() { return undefined === undefined; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), True)
-
-        jsi = JSInterpreter('''
-        function x() { return undefined; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), JS_Undefined)
-
-        jsi = JSInterpreter('''
-        function x() { let v; return v; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), JS_Undefined)
-
-        jsi = JSInterpreter('''
-        function x() { return [undefined === undefined, undefined == undefined, undefined < undefined, undefined > undefined]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [True, True, False, False])
-
-        jsi = JSInterpreter('''
-        function x() { return [undefined === 0, undefined == 0, undefined < 0, undefined > 0]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [False, False, False, False])
-
-        jsi = JSInterpreter('''
-        function x() { return [undefined >= 0, undefined <= 0]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [False, False])
-
-        jsi = JSInterpreter('''
-        function x() { return [undefined > null, undefined < null, undefined == null, undefined === null]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [False, False, True, False])
-
-        jsi = JSInterpreter('''
-        function x() { return [undefined === null, undefined == null, undefined < null, undefined > null]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [False, True, False, False])
-
-        jsi = JSInterpreter('''
-        function x() { let v; return [42+v, v+42, v**42, 42**v, 0**v]; }
-        ''')
-        for y in jsi.call_function('x'):
+        self._test('function f() { return undefined === undefined; }', True)
+        self._test('function f() { return undefined; }', JS_Undefined)
+        self._test('function f() {return undefined ?? 42; }', 42)
+        self._test('function f() { let v; return v; }', JS_Undefined)
+        self._test('function f() { let v; return v**0; }', 1)
+        self._test('function f() { let v; return [v>42, v<=42, v&&42, 42&&v]; }',
+                   [False, False, JS_Undefined, JS_Undefined])
+
+        self._test('''
+            function f() { return [
+                undefined === undefined,
+                undefined == undefined,
+                undefined == null,
+                undefined < undefined,
+                undefined > undefined,
+                undefined === 0,
+                undefined == 0,
+                undefined < 0,
+                undefined > 0,
+                undefined >= 0,
+                undefined <= 0,
+                undefined > null,
+                undefined < null,
+                undefined === null
+            ]; }
+        ''', list(map(bool, (1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0))))
+
+        jsi = JSInterpreter('''
+            function f() { let v; return [42+v, v+42, v**42, 42**v, 0**v]; }
+        ''')
+        for y in jsi.call_function('f'):
             self.assertTrue(math.isnan(y))
 
-        jsi = JSInterpreter('''
-        function x() { let v; return v**0; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 1)
-
-        jsi = JSInterpreter('''
-        function x() { let v; return [v>42, v<=42, v&&42, 42&&v]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [False, False, JS_Undefined, JS_Undefined])
-
-        jsi = JSInterpreter('function x(){return undefined ?? 42; }')
-        self.assertEqual(jsi.call_function('x'), 42)
-
     def test_object(self):
-        jsi = JSInterpreter('''
-        function x() { return {}; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), {})
-
-        jsi = JSInterpreter('''
-        function x() { let a = {m1: 42, m2: 0 }; return [a["m1"], a.m2]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [42, 0])
-
-        jsi = JSInterpreter('''
-        function x() { let a; return a?.qq; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), JS_Undefined)
-
-        jsi = JSInterpreter('''
-        function x() { let a = {m1: 42, m2: 0 }; return a?.qq; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), JS_Undefined)
+        self._test('function f() { return {}; }', {})
+        self._test('function f() { let a = {m1: 42, m2: 0 }; return [a["m1"], a.m2]; }', [42, 0])
+        self._test('function f() { let a; return a?.qq; }', JS_Undefined)
+        self._test('function f() { let a = {m1: 42, m2: 0 }; return a?.qq; }', JS_Undefined)
 
     def test_regex(self):
-        jsi = JSInterpreter('''
-        function x() { let a=/,,[/,913,/](,)}/; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), None)
+        self._test('function f() { let a=/,,[/,913,/](,)}/; }', None)
 
-        jsi = JSInterpreter('''
-        function x() { let a=/,,[/,913,/](,)}/; return a; }
-        ''')
-        self.assertIsInstance(jsi.call_function('x'), re.Pattern)
+        jsi = JSInterpreter('function f() { let a=/,,[/,913,/](,)}/; return a; }')
+        self.assertIsInstance(jsi.call_function('f'), re.Pattern)
 
-        jsi = JSInterpreter('''
-        function x() { let a=/,,[/,913,/](,)}/i; return a; }
-        ''')
-        self.assertEqual(jsi.call_function('x').flags & re.I, re.I)
+        jsi = JSInterpreter('function f() { let a=/,,[/,913,/](,)}/i; return a; }')
+        self.assertEqual(jsi.call_function('f').flags & re.I, re.I)
 
-        jsi = JSInterpreter(R'''
-        function x() { let a=/,][}",],()}(\[)/; return a; }
-        ''')
-        self.assertEqual(jsi.call_function('x').pattern, r',][}",],()}(\[)')
+        jsi = JSInterpreter(R'function f() { let a=/,][}",],()}(\[)/; return a; }')
+        self.assertEqual(jsi.call_function('f').pattern, r',][}",],()}(\[)')
 
-        jsi = JSInterpreter(R'''
-        function x() { let a=[/[)\\]/]; return a[0]; }
-        ''')
-        self.assertEqual(jsi.call_function('x').pattern, r'[)\\]')
+        jsi = JSInterpreter(R'function f() { let a=[/[)\\]/]; return a[0]; }')
+        self.assertEqual(jsi.call_function('f').pattern, r'[)\\]')
 
     def test_char_code_at(self):
-        jsi = JSInterpreter('function x(i){return "test".charCodeAt(i)}')
-        self.assertEqual(jsi.call_function('x', 0), 116)
-        self.assertEqual(jsi.call_function('x', 1), 101)
-        self.assertEqual(jsi.call_function('x', 2), 115)
-        self.assertEqual(jsi.call_function('x', 3), 116)
-        self.assertEqual(jsi.call_function('x', 4), None)
-        self.assertEqual(jsi.call_function('x', 'not_a_number'), 116)
+        jsi = JSInterpreter('function f(i){return "test".charCodeAt(i)}')
+        self.assertEqual(jsi.call_function('f', 0), 116)
+        self.assertEqual(jsi.call_function('f', 1), 101)
+        self.assertEqual(jsi.call_function('f', 2), 115)
+        self.assertEqual(jsi.call_function('f', 3), 116)
+        self.assertEqual(jsi.call_function('f', 4), None)
+        self.assertEqual(jsi.call_function('f', 'not_a_number'), 116)
 
     def test_bitwise_operators_overflow(self):
-        jsi = JSInterpreter('function x(){return -524999584 << 5}')
-        self.assertEqual(jsi.call_function('x'), 379882496)
-
-        jsi = JSInterpreter('function x(){return 1236566549 << 5}')
-        self.assertEqual(jsi.call_function('x'), 915423904)
+        self._test('function f(){return -524999584 << 5}', 379882496)
+        self._test('function f(){return 1236566549 << 5}', 915423904)
 
     def test_bitwise_operators_typecast(self):
-        jsi = JSInterpreter('function x(){return null << 5}')
-        self.assertEqual(jsi.call_function('x'), 0)
-
-        jsi = JSInterpreter('function x(){return undefined >> 5}')
-        self.assertEqual(jsi.call_function('x'), 0)
-
-        jsi = JSInterpreter('function x(){return 42 << NaN}')
-        self.assertEqual(jsi.call_function('x'), 42)
+        self._test('function f(){return null << 5}', 0)
+        self._test('function f(){return undefined >> 5}', 0)
+        self._test('function f(){return 42 << NaN}', 42)
 
     def test_negative(self):
-        jsi = JSInterpreter("function f(){return 2    *    -2.0;}")
-        self.assertEqual(jsi.call_function('f'), -4)
-
-        jsi = JSInterpreter('function f(){return 2    -    - -2;}')
-        self.assertEqual(jsi.call_function('f'), 0)
-
-        jsi = JSInterpreter('function f(){return 2    -    - - -2;}')
-        self.assertEqual(jsi.call_function('f'), 4)
-
-        jsi = JSInterpreter('function f(){return 2    -    + + - -2;}')
-        self.assertEqual(jsi.call_function('f'), 0)
-
-        jsi = JSInterpreter('function f(){return 2    +    - + - -2;}')
-        self.assertEqual(jsi.call_function('f'), 0)
+        self._test('function f(){return 2    *    -2.0    ;}', -4)
+        self._test('function f(){return 2    -    - -2    ;}', 0)
+        self._test('function f(){return 2    -    - - -2  ;}', 4)
+        self._test('function f(){return 2    -    + + - -2;}', 0)
+        self._test('function f(){return 2    +    - + - -2;}', 0)
 
 
 if __name__ == '__main__':