Make tests use \[ to escape brackets instead of [[ (#7521)

The main motivation here (though I also just like it more) is that
editor indentation modes won't get confused by unnested brackets when
editing test files in python-mode, which I do all the time.

Author: msullivan

mypy/test/data.py

@@ -424,7 +424,7 @@ def parse_test_data(raw_data: str, name: str) -> List[TestItem]:
     while i < len(lines):
         s = lines[i].strip()
 
-        if lines[i].startswith('[') and s.endswith(']') and not s.startswith('[['):
+        if lines[i].startswith('[') and s.endswith(']'):
             if id:
                 data = collapse_line_continuation(data)
                 data = strip_list(data)
@@ -437,7 +437,7 @@ def parse_test_data(raw_data: str, name: str) -> List[TestItem]:
                 arg = id[id.index(' ') + 1:]
                 id = id[:id.index(' ')]
             data = []
-        elif lines[i].startswith('[['):
+        elif lines[i].startswith('\\['):
             data.append(lines[i][1:])
         elif not lines[i].startswith('--'):
             data.append(lines[i])

mypyc/test-data/run.test

@@ -418,9 +418,8 @@ from native import primes
 print(primes(3))
 print(primes(13))
 [out]
-[[0, 0, 1, 1]
-[[0, 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1]
--- argh ]]
+\[0, 0, 1, 1]
+\[0, 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1]
 
 
 [case testListPrims]

test-data/unit/check-custom-plugin.test

@@ -8,15 +8,15 @@
 def f() -> str: ...
 reveal_type(f())  # N: Revealed type is 'builtins.int'
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/fnplugin.py
 
 [case testFunctionPlugin]
 # flags: --config-file tmp/mypy.ini
 def f() -> str: ...
 reveal_type(f())  # N: Revealed type is 'builtins.int'
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=fnplugin
 
 [case testFunctionPluginFullnameIsNotNone]
@@ -27,7 +27,7 @@ T = TypeVar('T')
 def g(x: T) -> T: return x  # This strips out the name of a callable
 g(f)()
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/fnplugin.py
 
 [case testTwoPlugins]
@@ -39,7 +39,7 @@ reveal_type(f())  # N: Revealed type is 'builtins.int'
 reveal_type(g())  # N: Revealed type is 'builtins.str'
 reveal_type(h())  # N: Revealed type is 'Any'
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/fnplugin.py,
   <ROOT>/test-data/unit/plugins/plugin2.py
 
@@ -52,13 +52,13 @@ reveal_type(f())  # N: Revealed type is 'builtins.int'
 reveal_type(g())  # N: Revealed type is 'builtins.str'
 reveal_type(h())  # N: Revealed type is 'Any'
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/fnplugin.py, plugin2
 
 [case testMissingPluginFile]
 # flags: --config-file tmp/mypy.ini
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=missing.py
 [out]
 tmp/mypy.ini:2: error: Can't find plugin 'tmp/missing.py'
@@ -67,19 +67,19 @@ tmp/mypy.ini:2: error: Can't find plugin 'tmp/missing.py'
 [case testMissingPlugin]
 # flags: --config-file tmp/mypy.ini
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=missing
 [out]
 tmp/mypy.ini:2: error: Error importing plugin 'missing'
 
 [case testMultipleSectionsDefinePlugin]
 # flags: --config-file tmp/mypy.ini
 [file mypy.ini]
-[[acme]
+\[acme]
 plugins=acmeplugin
-[[mypy]
+\[mypy]
 plugins=missing.py
-[[another]
+\[another]
 plugins=another_plugin
 [out]
 tmp/mypy.ini:4: error: Can't find plugin 'tmp/missing.py'
@@ -88,7 +88,7 @@ tmp/mypy.ini:4: error: Can't find plugin 'tmp/missing.py'
 [case testInvalidPluginExtension]
 # flags: --config-file tmp/mypy.ini
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=dir/badext.pyi
 [file dir/badext.pyi]
 [out]
@@ -97,7 +97,7 @@ tmp/mypy.ini:2: error: Plugin 'badext.pyi' does not have a .py extension
 [case testMissingPluginEntryPoint]
 # flags: --config-file tmp/mypy.ini
 [file mypy.ini]
-[[mypy]
+\[mypy]
  plugins = <ROOT>/test-data/unit/plugins/noentry.py
 [out]
 tmp/mypy.ini:2: error: Plugin '<ROOT>/test-data/unit/plugins/noentry.py' does not define entry point function "plugin"
@@ -107,23 +107,23 @@ tmp/mypy.ini:2: error: Plugin '<ROOT>/test-data/unit/plugins/noentry.py' does no
 def f() -> str: ...
 reveal_type(f())  # N: Revealed type is 'builtins.int'
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/customentry.py:register
 
 [case testCustomPluginEntryPoint]
 # flags: --config-file tmp/mypy.ini
 def f() -> str: ...
 reveal_type(f())  # N: Revealed type is 'builtins.int'
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=customentry:register
 
 [case testInvalidPluginEntryPointReturnValue]
 # flags: --config-file tmp/mypy.ini
 def f(): pass
 f()
 [file mypy.ini]
-[[mypy]
+\[mypy]
 
 plugins=<ROOT>/test-data/unit/plugins/badreturn.py
 [out]
@@ -134,7 +134,7 @@ tmp/mypy.ini:3: error: Type object expected as the return value of "plugin"; got
 def f(): pass
 f()
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/badreturn2.py
 [out]
 tmp/mypy.ini:2: error: Return value of "plugin" must be a subclass of "mypy.plugin.Plugin" (in <ROOT>/test-data/unit/plugins/badreturn2.py)
@@ -157,7 +157,7 @@ class Signal(Generic[T]):
 
 class DerivedSignal(Signal[T]): ...
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/attrhook.py
 
 [case testAttributeHookPluginForDynamicClass]
@@ -182,7 +182,7 @@ class Magic:
 class DerivedMagic(Magic): ...
 
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/attrhook2.py
 
 [case testTypeAnalyzeHookPlugin]
@@ -200,7 +200,7 @@ T = TypeVar('T', bound=Callable[..., None])
 class Signal(Generic[T]):
     __call__: Callable[..., None]
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/type_anal_hook.py
 [builtins fixtures/dict.pyi]
 
@@ -237,7 +237,7 @@ class AttrInt(Attr[int]):
         pass
 
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/class_callable.py
 [builtins fixtures/bool.pyi]
 [out]
@@ -256,7 +256,7 @@ from typing import Callable
 def decorator1() -> Callable[..., Callable[..., int]]: pass
 def decorator2() -> Callable[..., Callable[..., int]]: pass
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/named_callable.py
 
 [case testFunctionMethodContextsHasArgNames]
@@ -284,7 +284,7 @@ def func(classname: str, arg1: Any, arg2: Any) -> Any:
     pass
 
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/arg_names.py
 [builtins fixtures/classmethod.pyi]
 
@@ -313,7 +313,7 @@ def func(classname: str, arg1: Any, arg2: Any) -> Any:
     pass
 
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/arg_names.py
 [builtins fixtures/classmethod.pyi]
 
@@ -335,7 +335,7 @@ class Outer:
             pass
 
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/arg_names.py
 
 [case testFunctionMethodContextsHasArgNamesUnfilledArguments]
@@ -358,7 +358,7 @@ def func_unfilled(classname: str, arg1: Any = None, arg2: Any = None) -> Any:
     pass
 
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/arg_names.py
 
 [case testFunctionMethodContextsHasArgNamesStarExpressions]
@@ -382,7 +382,7 @@ def func_star_expr(classname: str, *args, **kwargs) -> Any:
     pass
 
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/arg_names.py
 [builtins fixtures/dict.pyi]
 
@@ -406,7 +406,7 @@ class ClassChild(Base):
     pass
 
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/arg_names.py
 [builtins fixtures/classmethod.pyi]
 
@@ -435,7 +435,7 @@ for x in foo:
     reveal_type(x) # N: Revealed type is 'builtins.int*'
 
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/method_sig_hook.py
 
 [case testMethodSignatureHookNamesFullyQualified]
@@ -459,7 +459,7 @@ reveal_type(FullyQualifiedTestClass().instance_method()) # N: Revealed type is '
 reveal_type(FullyQualifiedTestNamedTuple('')._asdict()) # N: Revealed type is 'builtins.int'
 
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/fully_qualified_test_hook.py
 [builtins fixtures/classmethod.pyi]
 
@@ -486,7 +486,7 @@ class Column(Generic[T]): ...
 class Instr(Generic[T]): ...
 
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/dyn_class.py
 
 [case testDynamicClassPluginNegatives]
@@ -513,7 +513,7 @@ class Column(Generic[T]): ...
 class Instr(Generic[T]): ...
 
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/dyn_class.py
 
 [case testBaseClassPluginHookWorksIncremental]
@@ -539,7 +539,7 @@ from typing import Any
 def declarative_base() -> Any: ...
 
 [file mypy.ini]
-[[mypy]
+\[mypy]
 python_version=3.6
 plugins=<ROOT>/test-data/unit/plugins/common_api_incremental.py
 [out]
@@ -556,7 +556,7 @@ class Class:
 Class().method(1, *[2], **{'a': 1})  # E: [[0, 2], [4]]
 [builtins fixtures/dict.pyi]
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/arg_kinds.py
 
 [case testArgKindsFunction]
@@ -567,7 +567,7 @@ def func(*args, **kwargs):
 func(1, 2, [3, 4], *[5, 6, 7], **{'a': 1})  # E: [[0, 0, 0, 2], [4]]
 [builtins fixtures/dict.pyi]
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/arg_kinds.py
 
 [case testHookCallableInstance]
@@ -582,7 +582,7 @@ instance = Class(3.14)
 reveal_type(instance(2))  # N: Revealed type is 'builtins.float*'
 
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/callable_instance.py
 
 [case testGetMethodHooksOnUnions]
@@ -604,7 +604,7 @@ else:
 
 [builtins fixtures/isinstancelist.pyi]
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/union_method.py
 
 [case testGetMethodHooksOnUnionsStrictOptional]
@@ -626,7 +626,7 @@ else:
 
 [builtins fixtures/isinstancelist.pyi]
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/union_method.py
 
 [case testGetMethodHooksOnUnionsSpecial]
@@ -643,7 +643,7 @@ reveal_type(x[int()])  # N: Revealed type is 'builtins.int'
 
 [builtins fixtures/isinstancelist.pyi]
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/union_method.py
 
 [case testPluginDependencies]
@@ -656,12 +656,12 @@ plugins=<ROOT>/test-data/unit/plugins/union_method.py
 1 + 'lol'  # E: Unsupported operand types for + ("int" and "str")
 
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/depshook.py
 
 [case testCustomizeMroTrivial]
 # flags: --config-file tmp/mypy.ini
 class A: pass
 [file mypy.ini]
-[[mypy]
+\[mypy]
 plugins=<ROOT>/test-data/unit/plugins/customize_mro.py