Python code coverage for Lib/test/test_fstring.py

#	count	content
1	n/a	import ast
2	n/a	import types
3	n/a	import decimal
4	n/a	import unittest
5	n/a
6	n/a	a_global = 'global variable'
7	n/a
8	n/a	# You could argue that I'm too strict in looking for specific error
9	n/a	# values with assertRaisesRegex, but without it it's way too easy to
10	n/a	# make a syntax error in the test strings. Especially with all of the
11	n/a	# triple quotes, raw strings, backslashes, etc. I think it's a
12	n/a	# worthwhile tradeoff. When I switched to this method, I found many
13	n/a	# examples where I wasn't testing what I thought I was.
14	n/a
15	n/a	class TestCase(unittest.TestCase):
16	n/a	def assertAllRaise(self, exception_type, regex, error_strings):
17	n/a	for str in error_strings:
18	n/a	with self.subTest(str=str):
19	n/a	with self.assertRaisesRegex(exception_type, regex):
20	n/a	eval(str)
21	n/a
22	n/a	def test__format__lookup(self):
23	n/a	# Make sure __format__ is looked up on the type, not the instance.
24	n/a	class X:
25	n/a	def __format__(self, spec):
26	n/a	return 'class'
27	n/a
28	n/a	x = X()
29	n/a
30	n/a	# Add a bound __format__ method to the 'y' instance, but not
31	n/a	# the 'x' instance.
32	n/a	y = X()
33	n/a	y.__format__ = types.MethodType(lambda self, spec: 'instance', y)
34	n/a
35	n/a	self.assertEqual(f'{y}', format(y))
36	n/a	self.assertEqual(f'{y}', 'class')
37	n/a	self.assertEqual(format(x), format(y))
38	n/a
39	n/a	# __format__ is not called this way, but still make sure it
40	n/a	# returns what we expect (so we can make sure we're bypassing
41	n/a	# it).
42	n/a	self.assertEqual(x.__format__(''), 'class')
43	n/a	self.assertEqual(y.__format__(''), 'instance')
44	n/a
45	n/a	# This is how __format__ is actually called.
46	n/a	self.assertEqual(type(x).__format__(x, ''), 'class')
47	n/a	self.assertEqual(type(y).__format__(y, ''), 'class')
48	n/a
49	n/a	def test_ast(self):
50	n/a	# Inspired by http://bugs.python.org/issue24975
51	n/a	class X:
52	n/a	def __init__(self):
53	n/a	self.called = False
54	n/a	def __call__(self):
55	n/a	self.called = True
56	n/a	return 4
57	n/a	x = X()
58	n/a	expr = """
59	n/a	a = 10
60	n/a	f'{a * x()}'"""
61	n/a	t = ast.parse(expr)
62	n/a	c = compile(t, '', 'exec')
63	n/a
64	n/a	# Make sure x was not called.
65	n/a	self.assertFalse(x.called)
66	n/a
67	n/a	# Actually run the code.
68	n/a	exec(c)
69	n/a
70	n/a	# Make sure x was called.
71	n/a	self.assertTrue(x.called)
72	n/a
73	n/a	def test_docstring(self):
74	n/a	def f():
75	n/a	f'''Not a docstring'''
76	n/a	self.assertIsNone(f.__doc__)
77	n/a	def g():
78	n/a	'''Not a docstring''' \
79	n/a	f''
80	n/a	self.assertIsNone(g.__doc__)
81	n/a
82	n/a	def test_literal_eval(self):
83	n/a	with self.assertRaisesRegex(ValueError, 'malformed node or string'):
84	n/a	ast.literal_eval("f'x'")
85	n/a
86	n/a	def test_ast_compile_time_concat(self):
87	n/a	x = ['']
88	n/a
89	n/a	expr = """x[0] = 'foo' f'{3}'"""
90	n/a	t = ast.parse(expr)
91	n/a	c = compile(t, '', 'exec')
92	n/a	exec(c)
93	n/a	self.assertEqual(x[0], 'foo3')
94	n/a
95	n/a	def test_compile_time_concat_errors(self):
96	n/a	self.assertAllRaise(SyntaxError,
97	n/a	'cannot mix bytes and nonbytes literals',
98	n/a	[r"""f'' b''""",
99	n/a	r"""b'' f''""",
100	n/a	])
101	n/a
102	n/a	def test_literal(self):
103	n/a	self.assertEqual(f'', '')
104	n/a	self.assertEqual(f'a', 'a')
105	n/a	self.assertEqual(f' ', ' ')
106	n/a
107	n/a	def test_unterminated_string(self):
108	n/a	self.assertAllRaise(SyntaxError, 'f-string: unterminated string',
109	n/a	[r"""f'{"x'""",
110	n/a	r"""f'{"x}'""",
111	n/a	r"""f'{("x'""",
112	n/a	r"""f'{("x}'""",
113	n/a	])
114	n/a
115	n/a	def test_mismatched_parens(self):
116	n/a	self.assertAllRaise(SyntaxError, 'f-string: mismatched',
117	n/a	["f'{((}'",
118	n/a	])
119	n/a
120	n/a	def test_double_braces(self):
121	n/a	self.assertEqual(f'{{', '{')
122	n/a	self.assertEqual(f'a{{', 'a{')
123	n/a	self.assertEqual(f'{{b', '{b')
124	n/a	self.assertEqual(f'a{{b', 'a{b')
125	n/a	self.assertEqual(f'}}', '}')
126	n/a	self.assertEqual(f'a}}', 'a}')
127	n/a	self.assertEqual(f'}}b', '}b')
128	n/a	self.assertEqual(f'a}}b', 'a}b')
129	n/a	self.assertEqual(f'{{}}', '{}')
130	n/a	self.assertEqual(f'a{{}}', 'a{}')
131	n/a	self.assertEqual(f'{{b}}', '{b}')
132	n/a	self.assertEqual(f'{{}}c', '{}c')
133	n/a	self.assertEqual(f'a{{b}}', 'a{b}')
134	n/a	self.assertEqual(f'a{{}}c', 'a{}c')
135	n/a	self.assertEqual(f'{{b}}c', '{b}c')
136	n/a	self.assertEqual(f'a{{b}}c', 'a{b}c')
137	n/a
138	n/a	self.assertEqual(f'{{{10}', '{10')
139	n/a	self.assertEqual(f'}}{10}', '}10')
140	n/a	self.assertEqual(f'}}{{{10}', '}{10')
141	n/a	self.assertEqual(f'}}a{{{10}', '}a{10')
142	n/a
143	n/a	self.assertEqual(f'{10}{{', '10{')
144	n/a	self.assertEqual(f'{10}}}', '10}')
145	n/a	self.assertEqual(f'{10}}}{{', '10}{')
146	n/a	self.assertEqual(f'{10}}}a{{' '}', '10}a{}')
147	n/a
148	n/a	# Inside of strings, don't interpret doubled brackets.
149	n/a	self.assertEqual(f'{"{{}}"}', '{{}}')
150	n/a
151	n/a	self.assertAllRaise(TypeError, 'unhashable type',
152	n/a	["f'{ {{}} }'", # dict in a set
153	n/a	])
154	n/a
155	n/a	def test_compile_time_concat(self):
156	n/a	x = 'def'
157	n/a	self.assertEqual('abc' f'## {x}ghi', 'abc## defghi')
158	n/a	self.assertEqual('abc' f'{x}' 'ghi', 'abcdefghi')
159	n/a	self.assertEqual('abc' f'{x}' 'gh' f'i{x:4}', 'abcdefghidef ')
160	n/a	self.assertEqual('{x}' f'{x}', '{x}def')
161	n/a	self.assertEqual('{x' f'{x}', '{xdef')
162	n/a	self.assertEqual('{x}' f'{x}', '{x}def')
163	n/a	self.assertEqual('{{x}}' f'{x}', '{{x}}def')
164	n/a	self.assertEqual('{{x' f'{x}', '{{xdef')
165	n/a	self.assertEqual('x}}' f'{x}', 'x}}def')
166	n/a	self.assertEqual(f'{x}' 'x}}', 'defx}}')
167	n/a	self.assertEqual(f'{x}' '', 'def')
168	n/a	self.assertEqual('' f'{x}' '', 'def')
169	n/a	self.assertEqual('' f'{x}', 'def')
170	n/a	self.assertEqual(f'{x}' '2', 'def2')
171	n/a	self.assertEqual('1' f'{x}' '2', '1def2')
172	n/a	self.assertEqual('1' f'{x}', '1def')
173	n/a	self.assertEqual(f'{x}' f'-{x}', 'def-def')
174	n/a	self.assertEqual('' f'', '')
175	n/a	self.assertEqual('' f'' '', '')
176	n/a	self.assertEqual('' f'' '' f'', '')
177	n/a	self.assertEqual(f'', '')
178	n/a	self.assertEqual(f'' '', '')
179	n/a	self.assertEqual(f'' '' f'', '')
180	n/a	self.assertEqual(f'' '' f'' '', '')
181	n/a
182	n/a	self.assertAllRaise(SyntaxError, "f-string: expecting '}'",
183	n/a	["f'{3' f'}'", # can't concat to get a valid f-string
184	n/a	])
185	n/a
186	n/a	def test_comments(self):
187	n/a	# These aren't comments, since they're in strings.
188	n/a	d = {'#': 'hash'}
189	n/a	self.assertEqual(f'{"#"}', '#')
190	n/a	self.assertEqual(f'{d["#"]}', 'hash')
191	n/a
192	n/a	self.assertAllRaise(SyntaxError, "f-string expression part cannot include '#'",
193	n/a	["f'{1#}'", # error because the expression becomes "(1#)"
194	n/a	"f'{3(#)}'",
195	n/a	"f'{#}'",
196	n/a	"f'{)#}'", # When wrapped in parens, this becomes
197	n/a	# '()#)'. Make sure that doesn't compile.
198	n/a	])
199	n/a
200	n/a	def test_many_expressions(self):
201	n/a	# Create a string with many expressions in it. Note that
202	n/a	# because we have a space in here as a literal, we're actually
203	n/a	# going to use twice as many ast nodes: one for each literal
204	n/a	# plus one for each expression.
205	n/a	def build_fstr(n, extra=''):
206	n/a	return "f'" + ('{x} ' * n) + extra + "'"
207	n/a
208	n/a	x = 'X'
209	n/a	width = 1
210	n/a
211	n/a	# Test around 256.
212	n/a	for i in range(250, 260):
213	n/a	self.assertEqual(eval(build_fstr(i)), (x+' ')*i)
214	n/a
215	n/a	# Test concatenating 2 largs fstrings.
216	n/a	self.assertEqual(eval(build_fstr(255)256), (x+' ')(255*256))
217	n/a
218	n/a	s = build_fstr(253, '{x:{width}} ')
219	n/a	self.assertEqual(eval(s), (x+' ')*254)
220	n/a
221	n/a	# Test lots of expressions and constants, concatenated.
222	n/a	s = "f'{1}' 'x' 'y'" * 1024
223	n/a	self.assertEqual(eval(s), '1xy' * 1024)
224	n/a
225	n/a	def test_format_specifier_expressions(self):
226	n/a	width = 10
227	n/a	precision = 4
228	n/a	value = decimal.Decimal('12.34567')
229	n/a	self.assertEqual(f'result: {value:{width}.{precision}}', 'result: 12.35')
230	n/a	self.assertEqual(f'result: {value:{width!r}.{precision}}', 'result: 12.35')
231	n/a	self.assertEqual(f'result: {value:{width:0}.{precision:1}}', 'result: 12.35')
232	n/a	self.assertEqual(f'result: {value:{1}{0:0}.{precision:1}}', 'result: 12.35')
233	n/a	self.assertEqual(f'result: {value:{ 1}{ 0:0}.{ precision:1}}', 'result: 12.35')
234	n/a	self.assertEqual(f'{10:#{1}0x}', ' 0xa')
235	n/a	self.assertEqual(f'{10:{"#"}1{0}{"x"}}', ' 0xa')
236	n/a	self.assertEqual(f'{-10:-{"#"}1{0}x}', ' -0xa')
237	n/a	self.assertEqual(f'{-10:{"-"}#{1}0{"x"}}', ' -0xa')
238	n/a	self.assertEqual(f'{10:#{3 != {4:5} and width}x}', ' 0xa')
239	n/a
240	n/a	self.assertAllRaise(SyntaxError, "f-string: expecting '}'",
241	n/a	["""f'{"s"!r{":10"}}'""",
242	n/a
243	n/a	# This looks like a nested format spec.
244	n/a	])
245	n/a
246	n/a	self.assertAllRaise(SyntaxError, "invalid syntax",
247	n/a	[# Invalid syntax inside a nested spec.
248	n/a	"f'{4:{/5}}'",
249	n/a	])
250	n/a
251	n/a	self.assertAllRaise(SyntaxError, "f-string: expressions nested too deeply",
252	n/a	[# Can't nest format specifiers.
253	n/a	"f'result: {value:{width:{0}}.{precision:1}}'",
254	n/a	])
255	n/a
256	n/a	self.assertAllRaise(SyntaxError, 'f-string: invalid conversion character',
257	n/a	[# No expansion inside conversion or for
258	n/a	# the : or ! itself.
259	n/a	"""f'{"s"!{"r"}}'""",
260	n/a	])
261	n/a
262	n/a	def test_side_effect_order(self):
263	n/a	class X:
264	n/a	def __init__(self):
265	n/a	self.i = 0
266	n/a	def __format__(self, spec):
267	n/a	self.i += 1
268	n/a	return str(self.i)
269	n/a
270	n/a	x = X()
271	n/a	self.assertEqual(f'{x} {x}', '1 2')
272	n/a
273	n/a	def test_missing_expression(self):
274	n/a	self.assertAllRaise(SyntaxError, 'f-string: empty expression not allowed',
275	n/a	["f'{}'",
276	n/a	"f'{ }'"
277	n/a	"f' {} '",
278	n/a	"f'{!r}'",
279	n/a	"f'{ !r}'",
280	n/a	"f'{10:{ }}'",
281	n/a	"f' { } '",
282	n/a
283	n/a	# Catch the empty expression before the
284	n/a	# invalid conversion.
285	n/a	"f'{!x}'",
286	n/a	"f'{ !xr}'",
287	n/a	"f'{!x:}'",
288	n/a	"f'{!x:a}'",
289	n/a	"f'{ !xr:}'",
290	n/a	"f'{ !xr:a}'",
291	n/a
292	n/a	"f'{!}'",
293	n/a	"f'{:}'",
294	n/a
295	n/a	# We find the empty expression before the
296	n/a	# missing closing brace.
297	n/a	"f'{!'",
298	n/a	"f'{!s:'",
299	n/a	"f'{:'",
300	n/a	"f'{:x'",
301	n/a	])
302	n/a
303	n/a	def test_parens_in_expressions(self):
304	n/a	self.assertEqual(f'{3,}', '(3,)')
305	n/a
306	n/a	# Add these because when an expression is evaluated, parens
307	n/a	# are added around it. But we shouldn't go from an invalid
308	n/a	# expression to a valid one. The added parens are just
309	n/a	# supposed to allow whitespace (including newlines).
310	n/a	self.assertAllRaise(SyntaxError, 'invalid syntax',
311	n/a	["f'{,}'",
312	n/a	"f'{,}'", # this is (,), which is an error
313	n/a	])
314	n/a
315	n/a	self.assertAllRaise(SyntaxError, "f-string: expecting '}'",
316	n/a	["f'{3)+(4}'",
317	n/a	])
318	n/a
319	n/a	self.assertAllRaise(SyntaxError, 'EOL while scanning string literal',
320	n/a	["f'{\n}'",
321	n/a	])
322	n/a
323	n/a	def test_backslashes_in_string_part(self):
324	n/a	self.assertEqual(f'\t', '\t')
325	n/a	self.assertEqual(r'\t', '\\t')
326	n/a	self.assertEqual(rf'\t', '\\t')
327	n/a	self.assertEqual(f'{2}\t', '2\t')
328	n/a	self.assertEqual(f'{2}\t{3}', '2\t3')
329	n/a	self.assertEqual(f'\t{3}', '\t3')
330	n/a
331	n/a	self.assertEqual(f'\u0394', '\u0394')
332	n/a	self.assertEqual(r'\u0394', '\\u0394')
333	n/a	self.assertEqual(rf'\u0394', '\\u0394')
334	n/a	self.assertEqual(f'{2}\u0394', '2\u0394')
335	n/a	self.assertEqual(f'{2}\u0394{3}', '2\u03943')
336	n/a	self.assertEqual(f'\u0394{3}', '\u03943')
337	n/a
338	n/a	self.assertEqual(f'\U00000394', '\u0394')
339	n/a	self.assertEqual(r'\U00000394', '\\U00000394')
340	n/a	self.assertEqual(rf'\U00000394', '\\U00000394')
341	n/a	self.assertEqual(f'{2}\U00000394', '2\u0394')
342	n/a	self.assertEqual(f'{2}\U00000394{3}', '2\u03943')
343	n/a	self.assertEqual(f'\U00000394{3}', '\u03943')
344	n/a
345	n/a	self.assertEqual(f'\N{GREEK CAPITAL LETTER DELTA}', '\u0394')
346	n/a	self.assertEqual(f'{2}\N{GREEK CAPITAL LETTER DELTA}', '2\u0394')
347	n/a	self.assertEqual(f'{2}\N{GREEK CAPITAL LETTER DELTA}{3}', '2\u03943')
348	n/a	self.assertEqual(f'\N{GREEK CAPITAL LETTER DELTA}{3}', '\u03943')
349	n/a	self.assertEqual(f'2\N{GREEK CAPITAL LETTER DELTA}', '2\u0394')
350	n/a	self.assertEqual(f'2\N{GREEK CAPITAL LETTER DELTA}3', '2\u03943')
351	n/a	self.assertEqual(f'\N{GREEK CAPITAL LETTER DELTA}3', '\u03943')
352	n/a
353	n/a	self.assertEqual(f'\x20', ' ')
354	n/a	self.assertEqual(r'\x20', '\\x20')
355	n/a	self.assertEqual(rf'\x20', '\\x20')
356	n/a	self.assertEqual(f'{2}\x20', '2 ')
357	n/a	self.assertEqual(f'{2}\x20{3}', '2 3')
358	n/a	self.assertEqual(f'\x20{3}', ' 3')
359	n/a
360	n/a	self.assertEqual(f'2\x20', '2 ')
361	n/a	self.assertEqual(f'2\x203', '2 3')
362	n/a	self.assertEqual(f'\x203', ' 3')
363	n/a
364	n/a	def test_misformed_unicode_character_name(self):
365	n/a	# These test are needed because unicode names are parsed
366	n/a	# differently inside f-strings.
367	n/a	self.assertAllRaise(SyntaxError, r"\(unicode error\) 'unicodeescape' codec can't decode bytes in position .*: malformed \\N character escape",
368	n/a	[r"f'\N'",
369	n/a	r"f'\N{'",
370	n/a	r"f'\N{GREEK CAPITAL LETTER DELTA'",
371	n/a
372	n/a	# Here are the non-f-string versions,
373	n/a	# which should give the same errors.
374	n/a	r"'\N'",
375	n/a	r"'\N{'",
376	n/a	r"'\N{GREEK CAPITAL LETTER DELTA'",
377	n/a	])
378	n/a
379	n/a	def test_no_backslashes_in_expression_part(self):
380	n/a	self.assertAllRaise(SyntaxError, 'f-string expression part cannot include a backslash',
381	n/a	[r"f'{\'a\'}'",
382	n/a	r"f'{\t3}'",
383	n/a	r"f'{\}'",
384	n/a	r"rf'{\'a\'}'",
385	n/a	r"rf'{\t3}'",
386	n/a	r"rf'{\}'",
387	n/a	r"""rf'{"\N{LEFT CURLY BRACKET}"}'""",
388	n/a	r"f'{\n}'",
389	n/a	])
390	n/a
391	n/a	def test_no_escapes_for_braces(self):
392	n/a	"""
393	n/a	Only literal curly braces begin an expression.
394	n/a	"""
395	n/a	# \x7b is '{'.
396	n/a	self.assertEqual(f'\x7b1+1}}', '{1+1}')
397	n/a	self.assertEqual(f'\x7b1+1', '{1+1')
398	n/a	self.assertEqual(f'\u007b1+1', '{1+1')
399	n/a	self.assertEqual(f'\N{LEFT CURLY BRACKET}1+1\N{RIGHT CURLY BRACKET}', '{1+1}')
400	n/a
401	n/a	def test_newlines_in_expressions(self):
402	n/a	self.assertEqual(f'{0}', '0')
403	n/a	self.assertEqual(rf'''{3+
404	n/a	4}''', '7')
405	n/a
406	n/a	def test_lambda(self):
407	n/a	x = 5
408	n/a	self.assertEqual(f'{(lambda y:x*y)("8")!r}', "'88888'")
409	n/a	self.assertEqual(f'{(lambda y:x*y)("8")!r:10}', "'88888' ")
410	n/a	self.assertEqual(f'{(lambda y:x*y)("8"):10}', "88888 ")
411	n/a
412	n/a	# lambda doesn't work without parens, because the colon
413	n/a	# makes the parser think it's a format_spec
414	n/a	self.assertAllRaise(SyntaxError, 'unexpected EOF while parsing',
415	n/a	["f'{lambda x:x}'",
416	n/a	])
417	n/a
418	n/a	def test_yield(self):
419	n/a	# Not terribly useful, but make sure the yield turns
420	n/a	# a function into a generator
421	n/a	def fn(y):
422	n/a	f'y:{yield y*2}'
423	n/a
424	n/a	g = fn(4)
425	n/a	self.assertEqual(next(g), 8)
426	n/a
427	n/a	def test_yield_send(self):
428	n/a	def fn(x):
429	n/a	yield f'x:{yield (lambda i: x * i)}'
430	n/a
431	n/a	g = fn(10)
432	n/a	the_lambda = next(g)
433	n/a	self.assertEqual(the_lambda(4), 40)
434	n/a	self.assertEqual(g.send('string'), 'x:string')
435	n/a
436	n/a	def test_expressions_with_triple_quoted_strings(self):
437	n/a	self.assertEqual(f"{'''x'''}", 'x')
438	n/a	self.assertEqual(f"{'''eric's'''}", "eric's")
439	n/a
440	n/a	# Test concatenation within an expression
441	n/a	self.assertEqual(f'{"x" """eric"s""" "y"}', 'xeric"sy')
442	n/a	self.assertEqual(f'{"x" """eric"s"""}', 'xeric"s')
443	n/a	self.assertEqual(f'{"""eric"s""" "y"}', 'eric"sy')
444	n/a	self.assertEqual(f'{"""x""" """eric"s""" "y"}', 'xeric"sy')
445	n/a	self.assertEqual(f'{"""x""" """eric"s""" """y"""}', 'xeric"sy')
446	n/a	self.assertEqual(f'{r"""x""" """eric"s""" """y"""}', 'xeric"sy')
447	n/a
448	n/a	def test_multiple_vars(self):
449	n/a	x = 98
450	n/a	y = 'abc'
451	n/a	self.assertEqual(f'{x}{y}', '98abc')
452	n/a
453	n/a	self.assertEqual(f'X{x}{y}', 'X98abc')
454	n/a	self.assertEqual(f'{x}X{y}', '98Xabc')
455	n/a	self.assertEqual(f'{x}{y}X', '98abcX')
456	n/a
457	n/a	self.assertEqual(f'X{x}Y{y}', 'X98Yabc')
458	n/a	self.assertEqual(f'X{x}{y}Y', 'X98abcY')
459	n/a	self.assertEqual(f'{x}X{y}Y', '98XabcY')
460	n/a
461	n/a	self.assertEqual(f'X{x}Y{y}Z', 'X98YabcZ')
462	n/a
463	n/a	def test_closure(self):
464	n/a	def outer(x):
465	n/a	def inner():
466	n/a	return f'x:{x}'
467	n/a	return inner
468	n/a
469	n/a	self.assertEqual(outer('987')(), 'x:987')
470	n/a	self.assertEqual(outer(7)(), 'x:7')
471	n/a
472	n/a	def test_arguments(self):
473	n/a	y = 2
474	n/a	def f(x, width):
475	n/a	return f'x={x*y:{width}}'
476	n/a
477	n/a	self.assertEqual(f('foo', 10), 'x=foofoo ')
478	n/a	x = 'bar'
479	n/a	self.assertEqual(f(10, 10), 'x= 20')
480	n/a
481	n/a	def test_locals(self):
482	n/a	value = 123
483	n/a	self.assertEqual(f'v:{value}', 'v:123')
484	n/a
485	n/a	def test_missing_variable(self):
486	n/a	with self.assertRaises(NameError):
487	n/a	f'v:{value}'
488	n/a
489	n/a	def test_missing_format_spec(self):
490	n/a	class O:
491	n/a	def __format__(self, spec):
492	n/a	if not spec:
493	n/a	return '*'
494	n/a	return spec
495	n/a
496	n/a	self.assertEqual(f'{O():x}', 'x')
497	n/a	self.assertEqual(f'{O()}', '*')
498	n/a	self.assertEqual(f'{O():}', '*')
499	n/a
500	n/a	self.assertEqual(f'{3:}', '3')
501	n/a	self.assertEqual(f'{3!s:}', '3')
502	n/a
503	n/a	def test_global(self):
504	n/a	self.assertEqual(f'g:{a_global}', 'g:global variable')
505	n/a	self.assertEqual(f'g:{a_global!r}', "g:'global variable'")
506	n/a
507	n/a	a_local = 'local variable'
508	n/a	self.assertEqual(f'g:{a_global} l:{a_local}',
509	n/a	'g:global variable l:local variable')
510	n/a	self.assertEqual(f'g:{a_global!r}',
511	n/a	"g:'global variable'")
512	n/a	self.assertEqual(f'g:{a_global} l:{a_local!r}',
513	n/a	"g:global variable l:'local variable'")
514	n/a
515	n/a	self.assertIn("module 'unittest' from", f'{unittest}')
516	n/a
517	n/a	def test_shadowed_global(self):
518	n/a	a_global = 'really a local'
519	n/a	self.assertEqual(f'g:{a_global}', 'g:really a local')
520	n/a	self.assertEqual(f'g:{a_global!r}', "g:'really a local'")
521	n/a
522	n/a	a_local = 'local variable'
523	n/a	self.assertEqual(f'g:{a_global} l:{a_local}',
524	n/a	'g:really a local l:local variable')
525	n/a	self.assertEqual(f'g:{a_global!r}',
526	n/a	"g:'really a local'")
527	n/a	self.assertEqual(f'g:{a_global} l:{a_local!r}',
528	n/a	"g:really a local l:'local variable'")
529	n/a
530	n/a	def test_call(self):
531	n/a	def foo(x):
532	n/a	return 'x=' + str(x)
533	n/a
534	n/a	self.assertEqual(f'{foo(10)}', 'x=10')
535	n/a
536	n/a	def test_nested_fstrings(self):
537	n/a	y = 5
538	n/a	self.assertEqual(f'{f"{0}"*3}', '000')
539	n/a	self.assertEqual(f'{f"{y}"*3}', '555')
540	n/a
541	n/a	def test_invalid_string_prefixes(self):
542	n/a	self.assertAllRaise(SyntaxError, 'unexpected EOF while parsing',
543	n/a	["fu''",
544	n/a	"uf''",
545	n/a	"Fu''",
546	n/a	"fU''",
547	n/a	"Uf''",
548	n/a	"uF''",
549	n/a	"ufr''",
550	n/a	"urf''",
551	n/a	"fur''",
552	n/a	"fru''",
553	n/a	"rfu''",
554	n/a	"ruf''",
555	n/a	"FUR''",
556	n/a	"Fur''",
557	n/a	"fb''",
558	n/a	"fB''",
559	n/a	"Fb''",
560	n/a	"FB''",
561	n/a	"bf''",
562	n/a	"bF''",
563	n/a	"Bf''",
564	n/a	"BF''",
565	n/a	])
566	n/a
567	n/a	def test_leading_trailing_spaces(self):
568	n/a	self.assertEqual(f'{ 3}', '3')
569	n/a	self.assertEqual(f'{ 3}', '3')
570	n/a	self.assertEqual(f'{3 }', '3')
571	n/a	self.assertEqual(f'{3 }', '3')
572	n/a
573	n/a	self.assertEqual(f'expr={ {x: y for x, y in [(1, 2), ]}}',
574	n/a	'expr={1: 2}')
575	n/a	self.assertEqual(f'expr={ {x: y for x, y in [(1, 2), ]} }',
576	n/a	'expr={1: 2}')
577	n/a
578	n/a	def test_not_equal(self):
579	n/a	# There's a special test for this because there's a special
580	n/a	# case in the f-string parser to look for != as not ending an
581	n/a	# expression. Normally it would, while looking for !s or !r.
582	n/a
583	n/a	self.assertEqual(f'{3!=4}', 'True')
584	n/a	self.assertEqual(f'{3!=4:}', 'True')
585	n/a	self.assertEqual(f'{3!=4!s}', 'True')
586	n/a	self.assertEqual(f'{3!=4!s:.3}', 'Tru')
587	n/a
588	n/a	def test_conversions(self):
589	n/a	self.assertEqual(f'{3.14:10.10}', ' 3.14')
590	n/a	self.assertEqual(f'{3.14!s:10.10}', '3.14 ')
591	n/a	self.assertEqual(f'{3.14!r:10.10}', '3.14 ')
592	n/a	self.assertEqual(f'{3.14!a:10.10}', '3.14 ')
593	n/a
594	n/a	self.assertEqual(f'{"a"}', 'a')
595	n/a	self.assertEqual(f'{"a"!r}', "'a'")
596	n/a	self.assertEqual(f'{"a"!a}', "'a'")
597	n/a
598	n/a	# Not a conversion.
599	n/a	self.assertEqual(f'{"a!r"}', "a!r")
600	n/a
601	n/a	# Not a conversion, but show that ! is allowed in a format spec.
602	n/a	self.assertEqual(f'{3.14:!<10.10}', '3.14!!!!!!')
603	n/a
604	n/a	self.assertAllRaise(SyntaxError, 'f-string: invalid conversion character',
605	n/a	["f'{3!g}'",
606	n/a	"f'{3!A}'",
607	n/a	"f'{3!3}'",
608	n/a	"f'{3!G}'",
609	n/a	"f'{3!!}'",
610	n/a	"f'{3!:}'",
611	n/a	"f'{3! s}'", # no space before conversion char
612	n/a	])
613	n/a
614	n/a	self.assertAllRaise(SyntaxError, "f-string: expecting '}'",
615	n/a	["f'{x!s{y}}'",
616	n/a	"f'{3!ss}'",
617	n/a	"f'{3!ss:}'",
618	n/a	"f'{3!ss:s}'",
619	n/a	])
620	n/a
621	n/a	def test_assignment(self):
622	n/a	self.assertAllRaise(SyntaxError, 'invalid syntax',
623	n/a	["f'' = 3",
624	n/a	"f'{0}' = x",
625	n/a	"f'{x}' = x",
626	n/a	])
627	n/a
628	n/a	def test_del(self):
629	n/a	self.assertAllRaise(SyntaxError, 'invalid syntax',
630	n/a	["del f''",
631	n/a	"del '' f''",
632	n/a	])
633	n/a
634	n/a	def test_mismatched_braces(self):
635	n/a	self.assertAllRaise(SyntaxError, "f-string: single '}' is not allowed",
636	n/a	["f'{{}'",
637	n/a	"f'{{}}}'",
638	n/a	"f'}'",
639	n/a	"f'x}'",
640	n/a	"f'x}x'",
641	n/a	r"f'\u007b}'",
642	n/a
643	n/a	# Can't have { or } in a format spec.
644	n/a	"f'{3:}>10}'",
645	n/a	"f'{3:}}>10}'",
646	n/a	])
647	n/a
648	n/a	self.assertAllRaise(SyntaxError, "f-string: expecting '}'",
649	n/a	["f'{3:{{>10}'",
650	n/a	"f'{3'",
651	n/a	"f'{3!'",
652	n/a	"f'{3:'",
653	n/a	"f'{3!s'",
654	n/a	"f'{3!s:'",
655	n/a	"f'{3!s:3'",
656	n/a	"f'x{'",
657	n/a	"f'x{x'",
658	n/a	"f'{x'",
659	n/a	"f'{3:s'",
660	n/a	"f'{{{'",
661	n/a	"f'{{}}{'",
662	n/a	"f'{'",
663	n/a	])
664	n/a
665	n/a	# But these are just normal strings.
666	n/a	self.assertEqual(f'{"{"}', '{')
667	n/a	self.assertEqual(f'{"}"}', '}')
668	n/a	self.assertEqual(f'{3:{"}"}>10}', '}}}}}}}}}3')
669	n/a	self.assertEqual(f'{2:{"{"}>10}', '{{{{{{{{{2')
670	n/a
671	n/a	def test_if_conditional(self):
672	n/a	# There's special logic in compile.c to test if the
673	n/a	# conditional for an if (and while) are constants. Exercise
674	n/a	# that code.
675	n/a
676	n/a	def test_fstring(x, expected):
677	n/a	flag = 0
678	n/a	if f'{x}':
679	n/a	flag = 1
680	n/a	else:
681	n/a	flag = 2
682	n/a	self.assertEqual(flag, expected)
683	n/a
684	n/a	def test_concat_empty(x, expected):
685	n/a	flag = 0
686	n/a	if '' f'{x}':
687	n/a	flag = 1
688	n/a	else:
689	n/a	flag = 2
690	n/a	self.assertEqual(flag, expected)
691	n/a
692	n/a	def test_concat_non_empty(x, expected):
693	n/a	flag = 0
694	n/a	if ' ' f'{x}':
695	n/a	flag = 1
696	n/a	else:
697	n/a	flag = 2
698	n/a	self.assertEqual(flag, expected)
699	n/a
700	n/a	test_fstring('', 2)
701	n/a	test_fstring(' ', 1)
702	n/a
703	n/a	test_concat_empty('', 2)
704	n/a	test_concat_empty(' ', 1)
705	n/a
706	n/a	test_concat_non_empty('', 1)
707	n/a	test_concat_non_empty(' ', 1)
708	n/a
709	n/a	def test_empty_format_specifier(self):
710	n/a	x = 'test'
711	n/a	self.assertEqual(f'{x}', 'test')
712	n/a	self.assertEqual(f'{x:}', 'test')
713	n/a	self.assertEqual(f'{x!s:}', 'test')
714	n/a	self.assertEqual(f'{x!r:}', "'test'")
715	n/a
716	n/a	def test_str_format_differences(self):
717	n/a	d = {'a': 'string',
718	n/a	0: 'integer',
719	n/a	}
720	n/a	a = 0
721	n/a	self.assertEqual(f'{d[0]}', 'integer')
722	n/a	self.assertEqual(f'{d["a"]}', 'string')
723	n/a	self.assertEqual(f'{d[a]}', 'integer')
724	n/a	self.assertEqual('{d[a]}'.format(d=d), 'string')
725	n/a	self.assertEqual('{d[0]}'.format(d=d), 'integer')
726	n/a
727	n/a	def test_invalid_expressions(self):
728	n/a	self.assertAllRaise(SyntaxError, 'invalid syntax',
729	n/a	[r"f'{a[4)}'",
730	n/a	r"f'{a(4]}'",
731	n/a	])
732	n/a
733	n/a	def test_errors(self):
734	n/a	# see issue 26287
735	n/a	self.assertAllRaise(TypeError, 'unsupported',
736	n/a	[r"f'{(lambda: 0):x}'",
737	n/a	r"f'{(0,):x}'",
738	n/a	])
739	n/a	self.assertAllRaise(ValueError, 'Unknown format code',
740	n/a	[r"f'{1000:j}'",
741	n/a	r"f'{1000:j}'",
742	n/a	])
743	n/a
744	n/a	def test_loop(self):
745	n/a	for i in range(1000):
746	n/a	self.assertEqual(f'i:{i}', 'i:' + str(i))
747	n/a
748	n/a	def test_dict(self):
749	n/a	d = {'"': 'dquote',
750	n/a	"'": 'squote',
751	n/a	'foo': 'bar',
752	n/a	}
753	n/a	self.assertEqual(f'''{d["'"]}''', 'squote')
754	n/a	self.assertEqual(f"""{d['"']}""", 'dquote')
755	n/a
756	n/a	self.assertEqual(f'{d["foo"]}', 'bar')
757	n/a	self.assertEqual(f"{d['foo']}", 'bar')
758	n/a
759	n/a	if __name__ == '__main__':
760	n/a	unittest.main()