A more convoluted #pragma once file identity test, using relative paths. (#1021)

* A more convoluted #pragma once file identity test, using relative paths.

* Fix bug with passing - to slang as a command line option causes a crash.
Ability to set file-system to use on command line.
#pragma once tests try with 'normal' and 'read-file' only versions

* OSFileSystem -> OSFileSystemExt
LoadFileOSFileSystem -> OSFileSystem

Implemented OSFileSystem like OSFileSystemExt as as singleton.
Fixes to comments.

4 files changed, 36 insertions, 0 deletions

diff --git a/tests/preprocessor/file-identity/b.h b/tests/preprocessor/file-identity/b.h
new file mode 100644
index 000000000..ba131c653
--- /dev/null
+++ b/tests/preprocessor/file-identity/b.h
@@ -0,0 +1,11 @@
+#pragma once
+
+#include "c.h"
+
+#ifdef B_H
+#   error "Shouldn't be included twice"
+#endif
+
+#define B_H
+
+float foo(float x) { return x; }
\ No newline at end of file
diff --git a/tests/preprocessor/file-identity/c.h b/tests/preprocessor/file-identity/c.h
new file mode 100644
index 000000000..eb6cd1c42
--- /dev/null
+++ b/tests/preprocessor/file-identity/c.h
@@ -0,0 +1,11 @@
+#pragma once
+
+#include "b.h"
+
+#ifdef C_H
+#   error "c.h shouldn't be included twice"
+#endif
+
+#define C_H
+
+float bar(float x) { return x; }
\ No newline at end of file
diff --git a/tests/preprocessor/file-identity/sub-folder/file-identity.slang b/tests/preprocessor/file-identity/sub-folder/file-identity.slang
new file mode 100644
index 000000000..590b32a70
--- /dev/null
+++ b/tests/preprocessor/file-identity/sub-folder/file-identity.slang
@@ -0,0 +1,13 @@
+//TEST(smoke):SIMPLE:
+//TEST(smoke):SIMPLE: -file-system load-file
+
+
+#include "../b.h"
+#include "../c.h"
+
+#include "./../b.h"
+
+float test(float x)
+{
+	return foo(x) + bar(x);
+}
\ No newline at end of file
diff --git a/tests/preprocessor/pragma-once.slang b/tests/preprocessor/pragma-once.slang
index 43ddee680..ef43ea265 100644
--- a/tests/preprocessor/pragma-once.slang
+++ b/tests/preprocessor/pragma-once.slang
@@ -1,4 +1,5 @@
 //TEST(smoke):SIMPLE:
+//TEST(smoke):SIMPLE: -file-system load-file
 
 // Test support for `#pragma once`