[FileCheck] Make Match unittest more flexible

[thopre]

Summary

FileCheck's Match unittest needs updating whenever some call to
initNextPattern() is inserted before its final block of checks. This
commit change usage of LineNumber inside the Tester object so that the
line number of the current pattern can be queries, thereby making the
Match test more solid.

[jhenderson]

llvm/unittests/Support/FileCheckTest.cpp

426–427

To make it clear that @LINE has been updated here, I'd recommend changing this phrase to "Check that @LINE matches the later line number." It might also be worthwhile putting a comment somewhere showing that initNextPattern updates the line number.

[thopre]

Address review comments

[jhenderson]

LGTM.

llvm/unittests/Support/FileCheckTest.cpp

 }
 
 class PatternTester {
 private:
   size_t LineNumber = 1;
   SourceMgr SM;
   FileCheckRequest Req;
   FileCheckPatternContext Context;
-  Pattern P{Check::CheckPlain, &Context, LineNumber++};
+  Pattern P{Check::CheckPlain, &Context, LineNumber};
 
 public:
   PatternTester() {
     std::vector<std::string> GlobalDefines;
     GlobalDefines.emplace_back(std::string("#FOO=42"));
     GlobalDefines.emplace_back(std::string("BAR=BAZ"));
     // An ASSERT_FALSE would make more sense but cannot be used in a
     // constructor.
     EXPECT_FALSE(
         errorToBool(Context.defineCmdlineVariables(GlobalDefines, SM)));
     Context.createLineVariable();
     // Call parsePattern to have @LINE defined.
     P.parsePattern("N/A", "CHECK", SM, Req);
     // parsePattern does not expect to be called twice for the same line and
     // will set FixedStr and RegExStr incorrectly if it is. Therefore prepare
     // a pattern for a different line.
     initNextPattern();
   }
 
   void initNextPattern() {
-    P = Pattern(Check::CheckPlain, &Context, LineNumber++);
+    P = Pattern(Check::CheckPlain, &Context, ++LineNumber);
   }
 
+  size_t getLineNumber() const { return LineNumber; }
+
   bool parseSubstExpect(StringRef Expr, bool IsLegacyLineExpr = false) {
     StringRef ExprBufferRef = bufferize(SM, Expr);
     Optional<NumericVariable *> DefinedNumericVariable;
     return errorToBool(P.parseNumericSubstitutionBlock(
                             ExprBufferRef, DefinedNumericVariable,
-                            IsLegacyLineExpr, LineNumber - 1, &Context, SM)
+                            IsLegacyLineExpr, LineNumber, &Context, SM)
                            .takeError());
   }
 
   bool parsePatternExpect(StringRef Pattern) {
     StringRef PatBufferRef = bufferize(SM, Pattern);
     return P.parsePattern(PatBufferRef, "CHECK", SM, Req);
   }
 
TEST_F(FileCheckTest, Match) {
   EXPECT_TRUE(Tester.matchExpect("19 21"));
   EXPECT_TRUE(Tester.matchExpect("18 21"));
   EXPECT_FALSE(Tester.matchExpect("18 20"));
 
   // Check matching a numeric expression using @LINE after match failure uses
   // the correct value for @LINE.
   Tester.initNextPattern();
   EXPECT_FALSE(Tester.parsePatternExpect("[[#@LINE]]"));
-  // Ok, @LINE is 7 now.
-  EXPECT_FALSE(Tester.matchExpect("7"));
+  // Ok, @LINE matches the current line number.
+  EXPECT_FALSE(Tester.matchExpect(std::to_string(Tester.getLineNumber())));
   Tester.initNextPattern();
-  // @LINE is now 8, match with substitution failure.
+  // Match with substitution failure.
   EXPECT_FALSE(Tester.parsePatternExpect("[[#UNKNOWN]]"));
   EXPECT_TRUE(Tester.matchExpect("FOO"));
   Tester.initNextPattern();
-  // Check that @LINE is 9 as expected.
+  // Check that @LINE matches the later (given the calls to initNextPattern())
+  // line number.
   EXPECT_FALSE(Tester.parsePatternExpect("[[#@LINE]]"));
-  EXPECT_FALSE(Tester.matchExpect("9"));
+  EXPECT_FALSE(Tester.matchExpect(std::to_string(Tester.getLineNumber())));
 }
 
 TEST_F(FileCheckTest, Substitution) {
   SourceMgr SM;
   FileCheckPatternContext Context;
   std::vector<std::string> GlobalDefines;
   GlobalDefines.emplace_back(std::string("FOO=BAR"));
   EXPECT_FALSE(errorToBool(Context.defineCmdlineVariables(GlobalDefines, SM)));