build: rework gtest checks

Rework gtest checks to be modeled after openbmc/gpioplus.

Change-Id: I54539c7031dbf87fea5d2c8ad56e415be8917f7a
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/configure.ac b/configure.ac
index 978df6a..79b27d8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -47,25 +47,74 @@
 # Checks for library functions.
 LT_INIT # Required for systemd linking
 
+# Make it possible for users to choose if they want test support
+# explicitly or not at all
+AC_ARG_ENABLE([tests], AC_HELP_STRING([--disable-tests],
+                                      [Build test cases]))
+
 # Check/set gtest specific functions.
-PKG_CHECK_MODULES(
-    [GTEST],
-    [gtest],
-    [],
-    [AC_MSG_NOTICE([gtest not found, tests will not build])]
-)
-PKG_CHECK_MODULES(
-    [GMOCK],
-    [gmock],
-    [],
-    [AC_MSG_NOTICE([gmock not found, tests will not build])]
-)
-PKG_CHECK_MODULES(
-    [GTEST_MAIN],
-    [gtest_main],
-    [],
-    [AC_MSG_NOTICE([gtest_main not found, tests will not build])]
-)
+AS_IF([test "x$enable_tests" != "xno"], [
+    PKG_CHECK_MODULES([GTEST], [gtest], [], [true])
+    PKG_CHECK_MODULES([GMOCK], [gmock], [], [true])
+    AX_PTHREAD
+
+    AX_SAVE_FLAGS_WITH_PREFIX(OLD, [CPPFLAGS])
+    AX_APPEND_COMPILE_FLAGS([$GTEST_CFLAGS], [CPPFLAGS])
+    AC_LANG_PUSH([C++])
+    AC_CHECK_HEADERS([gtest/gtest.h], [
+        AS_IF([test "x$GTEST_CFLAGS" = "x"], [
+            AS_IF([test "x$PTHREAD_CFLAGS" = "x"], [
+                AX_APPEND_COMPILE_FLAGS(["-DGTEST_HAS_PTHREAD=0"], [GTEST_CFLAGS])
+            ], [
+                AX_APPEND_COMPILE_FLAGS(["-DGTEST_HAS_PTHREAD=1"], [GTEST_CFLAGS])
+                AX_APPEND_COMPILE_FLAGS([$PTHREAD_CFLAGS], [GTEST_CFLAGS])
+            ])
+        ])
+    ], [
+        AS_IF([test "x$enable_tests" = "xyes"], [
+            AC_MSG_ERROR([Testing enabled but could not find gtest/gtest.h])
+        ])
+    ])
+    AC_LANG_POP([C++])
+    AX_RESTORE_FLAGS_WITH_PREFIX(OLD, [CPPFLAGS])
+
+    AX_SAVE_FLAGS_WITH_PREFIX(OLD, [CPPFLAGS])
+    AX_APPEND_COMPILE_FLAGS([$GMOCK_CFLAGS], [CPPFLAGS])
+    AC_LANG_PUSH([C++])
+    AC_CHECK_HEADERS([gmock/gmock.h], [], [
+        AS_IF([test "x$enable_tests" = "xyes"], [
+            AC_MSG_ERROR([Testing enabled but could not find gmock/gmock.h])
+        ])
+    ])
+    AC_LANG_POP([C++])
+    AX_RESTORE_FLAGS_WITH_PREFIX(OLD, [CPPFLAGS])
+
+    AX_SAVE_FLAGS_WITH_PREFIX(OLD, [LDFLAGS])
+    AX_APPEND_COMPILE_FLAGS([$GTEST_LIBS], [LDFLAGS])
+    AC_CHECK_LIB([gtest], [main], [
+        AS_IF([test "x$GTEST_LIBS" = "x"], [
+            AX_APPEND_COMPILE_FLAGS([-lgtest], [GTEST_LIBS])
+        ])
+    ], [
+        AS_IF([test "x$enable_tests" = "xyes"], [
+            AC_MSG_ERROR([Testing enabled but couldn't find gtest libs])
+        ])
+    ])
+    AX_RESTORE_FLAGS_WITH_PREFIX(OLD, [LDFLAGS])
+
+    AX_SAVE_FLAGS_WITH_PREFIX(OLD, [LDFLAGS])
+    AX_APPEND_COMPILE_FLAGS([$GMOCK_LIBS], [LDFLAGS])
+    AC_CHECK_LIB([gmock], [main], [
+        AS_IF([test "x$GMOCK_LIBS" = "x"], [
+            AX_APPEND_COMPILE_FLAGS([-lgmock], [GMOCK_LIBS])
+        ])
+    ], [
+        AS_IF([test "x$enable_tests" = "xyes"], [
+            AC_MSG_ERROR([Testing enabled but couldn't find gmock libs])
+        ])
+    ])
+    AX_RESTORE_FLAGS_WITH_PREFIX(OLD, [LDFLAGS])
+])
 
 AC_ARG_ENABLE([oe-sdk],
     AS_HELP_STRING(
diff --git a/test/Makefile.am b/test/Makefile.am
index 07c96ce..e2809f3 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -1,12 +1,14 @@
-AM_CPPFLAGS = -I$(top_srcdir)/ $(GTEST_CFLAGS) $(GMOCK_CFLAGS)
-AM_CXXFLAGS = \
-	$(GTEST_MAIN_CFLAGS) \
+AM_CPPFLAGS = \
+	-I$(top_srcdir)/ \
+	$(GTEST_CFLAGS) \
+	$(GMOCK_CFLAGS) \
 	$(SDBUSPLUS_CFLAGS) \
 	$(PHOSPHOR_DBUS_INTERFACES_CFLAGS) \
 	$(PHOSPHOR_LOGGING_CFLAGS)
 AM_LDFLAGS = \
+	$(GTEST_LIBS) \
 	$(GMOCK_LIBS) \
-	$(GTEST_MAIN_LIBS) \
+	-lgmock_main \
 	$(OESDK_TESTCASE_FLAGS) \
 	$(SDBUSPLUS_LIBS) \
 	$(PHOSPHOR_DBUS_INTERFACES_LIBS) \