[test] Modify test case so it verifies the fix from D126396

[MaskRay]

Thanks! The convention is to add [test] to test-only patches.
The subject line doesn't need a trailing .

You can change the Phabricator title, then run arc amend to amend the local commit.
I believe on Debian testing arc is somewhat broken with php 8, so you may need to get arc from https://github.com/phacility/arcanist (bin/arc)

clang/test/Preprocessor/file_test.c

16

This ./ line needs a comment about what is being tested.

[ppluzhnikov]

Add comment and suppress clang-format.

[ppluzhnikov]

Make comment better.

[ppluzhnikov]

Update.

[ppluzhnikov]

I think I've done the cleanups requested.

If this looks good, please push it (I don't have commit rights).

Thanks,

clang/test/Preprocessor/file_test.c

 // UNSUPPORTED: system-windows
 // RUN: %clang -E -ffile-prefix-map=%p=/UNLIKELY_PATH/empty -c -o - %s | FileCheck %s
 // RUN: %clang -E -fmacro-prefix-map=%p=/UNLIKELY_PATH/empty -c -o - %s | FileCheck %s
 // RUN: %clang -E -fmacro-prefix-map=%p=/UNLIKELY_PATH=empty -c -o - %s | FileCheck %s -check-prefix CHECK-EVIL
 // RUN: %clang -E -fmacro-prefix-map=%p/= -c -o - %s | FileCheck %s --check-prefix CHECK-REMOVE
 // RUN: %clang -E -fno-file-reproducible -fmacro-prefix-map=%p/= -target x86_64-pc-win32 -c -o - %s | FileCheck %s --check-prefix CHECK-REMOVE
 // RUN: %clang -E -fno-file-reproducible -ffile-prefix-map=%p/= -target x86_64-pc-win32 -c -o - %s | FileCheck %s --check-prefix CHECK-REMOVE
 // RUN: %clang -E -fmacro-prefix-map=%p/= -target x86_64-pc-win32 -c -o - %s | FileCheck %s --check-prefix CHECK-WINDOWS
 // RUN: %clang -E -ffile-prefix-map=%p/= -target x86_64-pc-win32 -c -o - %s | FileCheck %s --check-prefix CHECK-WINDOWS
 // RUN: %clang -E -ffile-reproducible -target x86_64-pc-win32 -c -o - %s | FileCheck %s --check-prefix CHECK-WINDOWS-REPRODUCIBLE
+// RUN: %clang -E -ffile-reproducible -target x86_64-pc-linux-gnu -c -o - %s | FileCheck %s --check-prefix CHECK-LINUX-REPRODUCIBLE
+
+/// Clang-format wants to do something unreasonable to this file.
+// clang-format off
 
 filename: __FILE__
-#include "Inputs/include-file-test/file_test.h"
+
+/// This line tests that the __FILE__ in included header is canonicalized
+/// (has "./" removed).
+#include "./Inputs/./include-file-test/file_test.h"
 
 // CHECK: filename: "/UNLIKELY_PATH/empty/file_test.c"
 // CHECK: filename: "/UNLIKELY_PATH/empty/Inputs/include-file-test/file_test.h"
 // CHECK: basefile: "/UNLIKELY_PATH/empty/file_test.c"
 // CHECK-NOT: filename:
 
 // CHECK-EVIL: filename: "/UNLIKELY_PATH=empty/file_test.c"
 // CHECK-EVIL: filename: "/UNLIKELY_PATH=empty/Inputs/include-file-test/file_test.h"
 // CHECK-EVIL: basefile: "/UNLIKELY_PATH=empty/file_test.c"
 // CHECK-EVIL-NOT: filename:
 
 // CHECK-REMOVE: filename: "file_test.c"
-// CHECK-REMOVE: filename: "Inputs/include-file-test/file_test.h"
+// CHECK-REMOVE: filename: "{{.*}}Inputs/{{.*}}include-file-test/file_test.h"
 // CHECK-REMOVE: basefile: "file_test.c"
 // CHECK-REMOVE-NOT: filename:
 
 // CHECK-WINDOWS: filename: "file_test.c"
 // CHECK-WINDOWS: filename: "Inputs\\include-file-test\\file_test.h"
 // CHECK-WINDOWS: basefile: "file_test.c"
 // CHECK-WINDOWS-NOT: filename:
 
-// CHECK-WINDOWS-REPRODUCIBLE: filename: "{{[^/]*}}file_test.c"
-// CHECK-WINDOWS-REPRODUCIBLE: filename: "{{[^/]*}}Inputs\\include-file-test\\file_test.h"
-// CHECK-WINDOWS-REPRODUCIBLE: basefile: "{{[^/]*}}file_test.c"
+// CHECK-WINDOWS-REPRODUCIBLE: filename: "{{.*}}\\file_test.c"
+// CHECK-WINDOWS-REPRODUCIBLE: filename: "{{.*}}\\Inputs\\include-file-test\\file_test.h"
+// CHECK-WINDOWS-REPRODUCIBLE: basefile: "{{.*}}\\file_test.c"
 // CHECK-WINDOWS-REPRODUCIBLE-NOT: filename:
+
+// CHECK-LINUX-REPRODUCIBLE: filename: "{{.*}}/file_test.c"
+// CHECK-LINUX-REPRODUCIBLE: filename: "{{.*}}/Inputs/include-file-test/file_test.h"
+// CHECK-LINUX-REPRODUCIBLE: basefile: "{{.*}}/file_test.c"
+// CHECK-LINUX-REPRODUCIBLE-NOT: filename: