Replace %/.format/concatenation with f-strings where feasible (#927)

Original conversion suggestions via flynt, edited by hand.

6 files changed, 17 insertions, 16 deletions

diff --git a/tests/messages/test_catalog.py b/tests/messages/test_catalog.py
index cc5fb49..e9b15a8 100644
--- a/tests/messages/test_catalog.py
+++ b/tests/messages/test_catalog.py
@@ -357,7 +357,7 @@ def test_catalog_mime_headers():
         ('MIME-Version', '1.0'),
         ('Content-Type', 'text/plain; charset=utf-8'),
         ('Content-Transfer-Encoding', '8bit'),
-        ('Generated-By', 'Babel %s\n' % catalog.VERSION),
+        ('Generated-By', f'Babel {catalog.VERSION}\n'),
     ]
 
 
@@ -380,7 +380,7 @@ def test_catalog_mime_headers_set_locale():
         ('MIME-Version', '1.0'),
         ('Content-Type', 'text/plain; charset=utf-8'),
         ('Content-Transfer-Encoding', '8bit'),
-        ('Generated-By', 'Babel %s\n' % catalog.VERSION),
+        ('Generated-By', f'Babel {catalog.VERSION}\n'),
     ]
 
 
diff --git a/tests/messages/test_frontend.py b/tests/messages/test_frontend.py
index 0eb7e8f..9e3ac9f 100644
--- a/tests/messages/test_frontend.py
+++ b/tests/messages/test_frontend.py
@@ -130,7 +130,7 @@ class ExtractMessagesTestCase(unittest.TestCase):
         assert ('file1.py' in msg.locations[0][0])
 
     def test_input_paths_handle_spaces_after_comma(self):
-        self.cmd.input_paths = '%s,  %s' % (this_dir, data_dir)
+        self.cmd.input_paths = f"{this_dir},  {data_dir}"
         self.cmd.output_file = pot_file
         self.cmd.finalize_options()
         assert self.cmd.input_paths == [this_dir, data_dir]
@@ -1118,7 +1118,7 @@ msgstr[2] ""
         self.cli.run(sys.argv + ['compile',
                                  '--locale', 'de_DE',
                                  '-d', i18n_dir])
-        assert not os.path.isfile(mo_file), 'Expected no file at %r' % mo_file
+        assert not os.path.isfile(mo_file), f'Expected no file at {mo_file!r}'
         assert sys.stderr.getvalue() == f'catalog {po_file} is marked as fuzzy, skipping\n'
 
     def test_compile_fuzzy_catalog(self):
@@ -1397,14 +1397,15 @@ def test_extract_keyword_args_384(split, arg_name):
     ]
 
     if split:  # Generate a command line with multiple -ks
-        kwarg_text = " ".join("%s %s" % (arg_name, kwarg_spec) for kwarg_spec in kwarg_specs)
+        kwarg_text = " ".join(f"{arg_name} {kwarg_spec}" for kwarg_spec in kwarg_specs)
     else:  # Generate a single space-separated -k
-        kwarg_text = "%s \"%s\"" % (arg_name, " ".join(kwarg_specs))
+        specs = ' '.join(kwarg_specs)
+        kwarg_text = f'{arg_name} "{specs}"'
 
     # (Both of those invocation styles should be equivalent, so there is no parametrization from here on out)
 
     cmdinst = configure_cli_command(
-        "extract -F babel-django.cfg --add-comments Translators: -o django232.pot %s ." % kwarg_text
+        f"extract -F babel-django.cfg --add-comments Translators: -o django232.pot {kwarg_text} ."
     )
     assert isinstance(cmdinst, extract_messages)
     assert set(cmdinst.keywords.keys()) == {'_', 'dgettext', 'dngettext',
@@ -1489,7 +1490,7 @@ def test_extract_error_code(monkeypatch, capsys):
 def test_extract_ignore_dirs(monkeypatch, capsys, tmp_path, with_underscore_ignore):
     pot_file = tmp_path / 'temp.pot'
     monkeypatch.chdir(project_dir)
-    cmd = "extract . -o '{}' --ignore-dirs '*ignored*' ".format(pot_file)
+    cmd = f"extract . -o '{pot_file}' --ignore-dirs '*ignored*' "
     if with_underscore_ignore:
         # This also tests that multiple arguments are supported.
         cmd += "--ignore-dirs '_*'"
diff --git a/tests/messages/test_pofile.py b/tests/messages/test_pofile.py
index 99e59ba..a72368b 100644
--- a/tests/messages/test_pofile.py
+++ b/tests/messages/test_pofile.py
@@ -859,7 +859,7 @@ class PofileFunctionsTestCase(unittest.TestCase):
         expected_denormalized = u'multi-line\n translation'
 
         assert expected_denormalized == pofile.denormalize(msgstr)
-        assert expected_denormalized == pofile.denormalize('""\n' + msgstr)
+        assert expected_denormalized == pofile.denormalize(f'""\n{msgstr}')
 
 
 def test_unknown_language_roundtrip():
diff --git a/tests/test_core.py b/tests/test_core.py
index 2de79e2..605bf5c 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -309,8 +309,7 @@ def test_compatible_classes_in_global_and_localedata(filename):
             # *.dat files must have compatible classes between Python 2 and 3
             if module.split('.')[0] == 'babel':
                 return pickle.Unpickler.find_class(self, module, name)
-            raise pickle.UnpicklingError("global '%s.%s' is forbidden" %
-                                         (module, name))
+            raise pickle.UnpicklingError(f"global '{module}.{name}' is forbidden")
 
     with open(filename, 'rb') as f:
         assert Unpickler(f).load()
diff --git a/tests/test_plural.py b/tests/test_plural.py
index 4210033..16601cf 100644
--- a/tests/test_plural.py
+++ b/tests/test_plural.py
@@ -273,7 +273,7 @@ def test_gettext_compilation(locale):
     chars = 'ivwft'
     # Test that these rules are valid for this test; i.e. that they contain at least one
     # of the gettext-unsupported characters.
-    assert any((" " + ch + " ") in rule for ch in chars for rule in ru_rules.values())
+    assert any(f" {ch} " in rule for ch in chars for rule in ru_rules.values())
     # Then test that the generated value indeed does not contain these.
     ru_rules_gettext = plural.to_gettext(ru_rules)
     assert not any(ch in ru_rules_gettext for ch in chars)
diff --git a/tests/test_support.py b/tests/test_support.py
index 9447107..c73e53b 100644
--- a/tests/test_support.py
+++ b/tests/test_support.py
@@ -63,8 +63,7 @@ class TranslationsTestCase(unittest.TestCase):
 
     def assertEqualTypeToo(self, expected, result):
         assert expected == result
-        assert type(expected) == type(result), "instance type's do not " + \
-            "match: %r!=%r" % (type(expected), type(result))
+        assert type(expected) == type(result), f"instance types do not match: {type(expected)!r}!={type(result)!r}"
 
     def test_pgettext(self):
         self.assertEqualTypeToo('Voh', self.translations.gettext('foo'))
@@ -210,7 +209,7 @@ class NullTranslationsTestCase(unittest.TestCase):
     def test_same_methods(self):
         for name in self.method_names():
             if not hasattr(self.null_translations, name):
-                self.fail('NullTranslations does not provide method %r' % name)
+                self.fail(f"NullTranslations does not provide method {name!r}")
 
     def test_method_signature_compatibility(self):
         for name in self.method_names():
@@ -346,11 +345,13 @@ def test_format_percent():
 
 def test_lazy_proxy():
     def greeting(name='world'):
-        return u'Hello, %s!' % name
+        return f"Hello, {name}!"
+
     lazy_greeting = support.LazyProxy(greeting, name='Joe')
     assert str(lazy_greeting) == u"Hello, Joe!"
     assert u'  ' + lazy_greeting == u'  Hello, Joe!'
     assert u'(%s)' % lazy_greeting == u'(Hello, Joe!)'
+    assert f"[{lazy_greeting}]" == "[Hello, Joe!]"
 
     greetings = [
         support.LazyProxy(greeting, 'world'),