Add unit tests for StringSwitch.

[zturner]

Summary

Adds unit tests for Case, Cases, StartsWith, and EndsWith with a variety of different argument types.

[zturner]

I'll hold off on uploading the other patches, since how I write the tests for the lower versions depends on what your comments are on this patch.

[chandlerc]

I was all prepared to not like this approach for testing. But it looks really, really nice. I've got nothing to really suggest here other than some test cases you should probably add:

• purely length-delimited cases.
• edge cases with '\0' bytes in the middle of the string
  • '\0' in the middle of the case
  • '\0' in the middle of the input

For the latter: I think the formation of the StringRef will handle all of this and you'll just show that whatever length the StringRef has, that's the length that is used. But good to document this fact so folks don't go and switch the code to use strncmp for some weird reason.

Feel free to submit with whatever you come up with here.

unittests/ADT/CMakeLists.txt

set(ADTSources
   SmallStringTest.cpp
   SmallVectorTest.cpp
   SparseBitVectorTest.cpp
   SparseMultiSetTest.cpp
   SparseSetTest.cpp
   StringExtrasTest.cpp
   StringMapTest.cpp
   StringRefTest.cpp
+  StringSwitchTest.cpp
   TinyPtrVectorTest.cpp
   TripleTest.cpp
   TwineTest.cpp
   VariadicFunctionTest.cpp
  )
 
 add_llvm_unittest(ADTTests
   ${ADTSources}
   )
 
 add_dependencies(ADTTests intrinsics_gen)

unittests/ADT/StringSwitchTest.cpp

+//===- llvm/unittest/ADT/StringSwitchTest.cpp - StringSwitch unit tests ---===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/StringSwitch.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+TEST(StringSwitchTest, Case) {
+  auto Translate = [](StringRef S) {
+    return llvm::StringSwitch<int>(S)
+        .Case("0", 0)
+        .Case("1", 1)
+        .Case("2", 2)
+        .Case("3", 3)
+        .Case("4", 4)
+        .Case("5", 5)
+        .Case("6", 6)
+        .Case("7", 7)
+        .Case("8", 8)
+        .Case("9", 9)
+        .Case("A", 10)
+        .Case("B", 11)
+        .Case("C", 12)
+        .Case("D", 13)
+        .Case("E", 14)
+        .Case("F", 15)
+        .Default(-1);
+  };
+  EXPECT_EQ(1, Translate("1"));
+  EXPECT_EQ(2, Translate("2"));
+  EXPECT_EQ(11, Translate("B"));
+  EXPECT_EQ(-1, Translate("b"));
+  EXPECT_EQ(-1, Translate(""));
+  EXPECT_EQ(-1, Translate("Test"));
+}
+
+TEST(StringSwitchTest, StartsWith) {
+  auto Translate = [](StringRef S) {
+    return llvm::StringSwitch<std::function<int(int, int)>>(S)
+        .StartsWith("add", [](int X, int Y) { return X + Y; })
+        .StartsWith("sub", [](int X, int Y) { return X - Y; })
+        .StartsWith("mul", [](int X, int Y) { return X * Y; })
+        .StartsWith("div", [](int X, int Y) { return X / Y; })
+        .Default([](int X, int Y) { return 0; });
+  };
+
+  EXPECT_EQ(15, Translate("adder")(10, 5));
+  EXPECT_EQ(5, Translate("subtracter")(10, 5));
+  EXPECT_EQ(50, Translate("multiplier")(10, 5));
+  EXPECT_EQ(2, Translate("divider")(10, 5));
+
+  EXPECT_EQ(0, Translate("nothing")(10, 5));
+  EXPECT_EQ(0, Translate("ADDER")(10, 5));
+}
+
+TEST(StringSwitchTest, EndsWith) {
+  enum class Suffix { Possible, PastTense, Process, InProgressAction, Unknown };
+
+  auto Translate = [](StringRef S) {
+    return llvm::StringSwitch<Suffix>(S)
+        .EndsWith("able", Suffix::Possible)
+        .EndsWith("ed", Suffix::PastTense)
+        .EndsWith("ation", Suffix::Process)
+        .EndsWith("ing", Suffix::InProgressAction)
+        .Default(Suffix::Unknown);
+  };
+
+  EXPECT_EQ(Suffix::Possible, Translate("optimizable"));
+  EXPECT_EQ(Suffix::PastTense, Translate("optimized"));
+  EXPECT_EQ(Suffix::Process, Translate("optimization"));
+  EXPECT_EQ(Suffix::InProgressAction, Translate("optimizing"));
+  EXPECT_EQ(Suffix::Unknown, Translate("optimizer"));
+  EXPECT_EQ(Suffix::Unknown, Translate("OPTIMIZABLE"));
+}
+
+TEST(StringSwitchTest, Cases) {
+  enum class OSType { Windows, Linux, Unknown };
+
+  auto Translate = [](StringRef S) {
+    return llvm::StringSwitch<OSType>(S)
+        .Cases("windows", "win32", "winnt", OSType::Windows)
+        .Cases("linux", "unix", "*nix", "posix", OSType::Linux)
+        .Default(OSType::Unknown);
+  };
+
+  EXPECT_EQ(OSType::Windows, Translate("windows"));
+  EXPECT_EQ(OSType::Windows, Translate("win32"));
+  EXPECT_EQ(OSType::Windows, Translate("winnt"));
+
+  EXPECT_EQ(OSType::Linux, Translate("linux"));
+  EXPECT_EQ(OSType::Linux, Translate("unix"));
+  EXPECT_EQ(OSType::Linux, Translate("*nix"));
+  EXPECT_EQ(OSType::Linux, Translate("posix"));
+
+  EXPECT_EQ(OSType::Unknown, Translate("Windows"));
+  EXPECT_EQ(OSType::Unknown, Translate(""));
+}