[clang-format] Refactor ObjC tests

[jolesiak]

Summary

Simplifies ObjC style tests.

Test Plan: make -j12 FormatTests && tools/clang/unittests/Format/FormatTests --gtest_filter=FormatTestObjCStyle*

[krasimir]

I don't believe this is needed: test fails before would fail at the line where test instance is checked, and after they will fail at the checkLanguage function.

[jolesiak]

In D43231#1006123, @krasimir wrote:

I don't believe this is needed: test fails before would fail at the line where test instance is checked, and after they will fail at the checkLanguage function.

Thank you for the comment!
That's a valid argument. I'm reverting as a macro is a no go.

unittests/Format/FormatTestObjC.cpp

protected:
 
   void verifyIncompleteFormat(StringRef Code) {
     EXPECT_EQ(Code.str(), format(test::messUp(Code), SC_ExpectIncomplete));
   }
 
   FormatStyle Style;
 };
 
+// Checks whether language detected after running \p getStyle is expected.
+// \p Style cannot be a reference to const as casting to bool can change
+// internal state.
+void checkLanguage(llvm::Expected<FormatStyle> &Style,
+                   FormatStyle::LanguageKind ExpectedLanguage) {
+  ASSERT_TRUE((bool)Style);
+  EXPECT_EQ(ExpectedLanguage, Style->Language);
+}
+
 TEST(FormatTestObjCStyle, DetectsObjCInHeaders) {
   auto Style = getStyle("LLVM", "a.h", "none", "@interface\n"
                                                "- (id)init;");
-  ASSERT_TRUE((bool)Style);
-  EXPECT_EQ(FormatStyle::LK_ObjC, Style->Language);
+  checkLanguage(Style, FormatStyle::LK_ObjC);
 
   Style = getStyle("LLVM", "a.h", "none", "@interface\n"
                                           "+ (id)init;");
-  ASSERT_TRUE((bool)Style);
-  EXPECT_EQ(FormatStyle::LK_ObjC, Style->Language);
+  checkLanguage(Style, FormatStyle::LK_ObjC);
 
   Style = getStyle("LLVM", "a.h", "none", "@interface\n"
                                           "@end\n"
                                           "//comment");
-  ASSERT_TRUE((bool)Style);
-  EXPECT_EQ(FormatStyle::LK_ObjC, Style->Language);
+  checkLanguage(Style, FormatStyle::LK_ObjC);
 
   Style = getStyle("LLVM", "a.h", "none", "@interface\n"
                                           "@end //comment");
-  ASSERT_TRUE((bool)Style);
-  EXPECT_EQ(FormatStyle::LK_ObjC, Style->Language);
+  checkLanguage(Style, FormatStyle::LK_ObjC);
 
   // No recognizable ObjC.
   Style = getStyle("LLVM", "a.h", "none", "void f() {}");
-  ASSERT_TRUE((bool)Style);
-  EXPECT_EQ(FormatStyle::LK_Cpp, Style->Language);
+  checkLanguage(Style, FormatStyle::LK_Cpp);
 
   Style = getStyle("{}", "a.h", "none", "@interface Foo\n@end\n");
-  ASSERT_TRUE((bool)Style);
-  EXPECT_EQ(FormatStyle::LK_ObjC, Style->Language);
+  checkLanguage(Style, FormatStyle::LK_ObjC);
 
   Style = getStyle("{}", "a.h", "none",
                    "const int interface = 1;\nconst int end = 2;\n");
-  ASSERT_TRUE((bool)Style);
-  EXPECT_EQ(FormatStyle::LK_Cpp, Style->Language);
+  checkLanguage(Style, FormatStyle::LK_Cpp);
 
   Style = getStyle("{}", "a.h", "none", "@protocol Foo\n@end\n");
-  ASSERT_TRUE((bool)Style);
-  EXPECT_EQ(FormatStyle::LK_ObjC, Style->Language);
+  checkLanguage(Style, FormatStyle::LK_ObjC);
 
   Style = getStyle("{}", "a.h", "none",
                    "const int protocol = 1;\nconst int end = 2;\n");
-  ASSERT_TRUE((bool)Style);
-  EXPECT_EQ(FormatStyle::LK_Cpp, Style->Language);
-
-  Style = getStyle("{}", "a.h", "none", "extern NSString *kFoo;\n");
-  ASSERT_TRUE((bool)Style);
-  EXPECT_EQ(FormatStyle::LK_ObjC, Style->Language);
+  checkLanguage(Style, FormatStyle::LK_Cpp);
 
   Style =
       getStyle("{}", "a.h", "none", "typedef NS_ENUM(NSInteger, Foo) {};\n");
-  ASSERT_TRUE((bool)Style);
-  EXPECT_EQ(FormatStyle::LK_ObjC, Style->Language);
+  checkLanguage(Style, FormatStyle::LK_ObjC);
 
   Style = getStyle("{}", "a.h", "none", "enum Foo {};");
-  ASSERT_TRUE((bool)Style);
-  EXPECT_EQ(FormatStyle::LK_Cpp, Style->Language);
-
-  Style = getStyle("{}", "a.h", "none", "extern NSInteger Foo();\n");
-  ASSERT_TRUE((bool)Style);
-  EXPECT_EQ(FormatStyle::LK_ObjC, Style->Language);
+  checkLanguage(Style, FormatStyle::LK_Cpp);
 
   Style =
       getStyle("{}", "a.h", "none", "inline void Foo() { Log(@\"Foo\"); }\n");
-  ASSERT_TRUE((bool)Style);
-  EXPECT_EQ(FormatStyle::LK_ObjC, Style->Language);
+  checkLanguage(Style, FormatStyle::LK_ObjC);
 
   Style =
       getStyle("{}", "a.h", "none", "inline void Foo() { Log(\"Foo\"); }\n");
-  ASSERT_TRUE((bool)Style);
-  EXPECT_EQ(FormatStyle::LK_Cpp, Style->Language);
+  checkLanguage(Style, FormatStyle::LK_Cpp);
 
   Style =
       getStyle("{}", "a.h", "none", "inline void Foo() { id = @[1, 2, 3]; }\n");
-  ASSERT_TRUE((bool)Style);
-  EXPECT_EQ(FormatStyle::LK_ObjC, Style->Language);
+  checkLanguage(Style, FormatStyle::LK_ObjC);
 
   Style = getStyle("{}", "a.h", "none",
                    "inline void Foo() { id foo = @{1: 2, 3: 4, 5: 6}; }\n");
-  ASSERT_TRUE((bool)Style);
-  EXPECT_EQ(FormatStyle::LK_ObjC, Style->Language);
+  checkLanguage(Style, FormatStyle::LK_ObjC);
 
   Style = getStyle("{}", "a.h", "none",
                    "inline void Foo() { int foo[] = {1, 2, 3}; }\n");
-  ASSERT_TRUE((bool)Style);
-  EXPECT_EQ(FormatStyle::LK_Cpp, Style->Language);
+  checkLanguage(Style, FormatStyle::LK_Cpp);
+
+  // ObjC specific types.
+  Style = getStyle("{}", "a.h", "none", "extern NSString *kFoo;\n");
+  checkLanguage(Style, FormatStyle::LK_ObjC);
+
+  Style = getStyle("{}", "a.h", "none", "extern NSInteger Foo();\n");
+  checkLanguage(Style, FormatStyle::LK_ObjC);
 }
 
 TEST_F(FormatTestObjC, FormatObjCTryCatch) {
   verifyFormat("@try {\n"
                "  f();\n"
                "} @catch (NSException e) {\n"
                "  @throw;\n"
                "} @finally {\n"