Include test sources to pick up functions and classes from the module…

… rather than from the non-modular library that's baked into the `test-main` library.

This avoids linker problems:
 - strong ownership model: missing linker symbols
 - weak ownership model: duplicate linker symbols

test/CMakeLists.txt

@@ -41,7 +41,7 @@ function(add_fmt_test name)
       set(PEDANTIC_COMPILE_FLAGS ${PEDANTIC_COMPILE_FLAGS} -Wno-weak-vtables)
     endif ()
   elseif (ADD_FMT_TEST_MODULE)
-    set(libs test-main test-module)
+    set(libs gtest test-module)
     set_source_files_properties(${name}.cc PROPERTIES OBJECT_DEPENDS test-module)
   else ()
     set(libs test-main fmt)
@@ -97,7 +97,7 @@ if (FMT_CAN_MODULE)
     $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>)
   enable_module(test-module)
 
-  add_fmt_test(module-test MODULE)
+  add_fmt_test(module-test MODULE test-main.cc)
   if (MSVC)
     target_compile_options(test-module PRIVATE /utf-8)
     target_compile_options(module-test PRIVATE /utf-8)

test/module-test.cc

@@ -35,18 +35,41 @@
 #  define FMT_USE_FCNTL 0
 #endif
 #define FMT_NOEXCEPT noexcept
+#ifndef FMT_POSIX
+#  if defined(_WIN32) && !defined(__MINGW32__)
+#    define FMT_POSIX(call) _##call
+#  else
+#    define FMT_POSIX(call) call
+#  endif
+#endif
+#ifndef _WIN32
+#  define FMT_RETRY_VAL(result, expression, error_result) \
+    do {                                                  \
+      (result) = (expression);                            \
+    } while ((result) == (error_result) && errno == EINTR)
+#else
+#  define FMT_RETRY_VAL(result, expression, error_result) result = (expression)
+#endif
+#define FMT_RETRY(result, expression) FMT_RETRY_VAL(result, expression, -1)
+#define FMT_OS_H_
 
 import fmt;
 
 // check for macros leaking from BMI
 static bool macro_leaked =
-#if defined(FMT_CORE_H_) || defined(FMT_FORMAT_H)
+#if defined(FMT_CORE_H_) || defined(FMT_FORMAT_H_)
     true;
 #else
     false;
 #endif
 
-#include "gtest-extra.h"
+// Include sources to pick up functions and classes from the module rather than
+// from the non-modular library that's baked into the 'test-main' library.
+// This avoids linker problems:
+// - strong ownership model: missing linker symbols
+// - weak ownership model: duplicate linker symbols
+#include "gtest-extra.cc"
+#include "util.cc"
 
 // an implicitly exported namespace must be visible [module.interface]/2.2
 TEST(module_test, namespace) {