build: add gtest, gmock to configure_ac

Search for gtest and gmock through configure_ac so
that their presence is required before usage.

Change-Id: I719e2d2474b148402b33c9af97075f42b4cc0afe
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/configure.ac b/configure.ac
index 5ecdab0..bb32ad6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -33,9 +33,70 @@
 # Code coverage
 AX_CODE_COVERAGE
 
+# 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.
-AX_PTHREAD([GTEST_CPPFLAGS="-DGTEST_HAS_PTHREAD=1"],[GTEST_CPPFLAGS="-DGTEST_HAS_PTHREAD=0"])
-AC_SUBST(GTEST_CPPFLAGS)
+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_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])
+        ])
+    ])
+    AX_RESTORE_FLAGS_WITH_PREFIX(OLD, [CPPFLAGS])
+
+    AX_SAVE_FLAGS_WITH_PREFIX(OLD, [CPPFLAGS])
+    AX_APPEND_COMPILE_FLAGS([$GMOCK_CFLAGS], [CPPFLAGS])
+    AC_CHECK_HEADERS([gmock/gmock.h], [], [
+        AS_IF([test "x$enable_tests" = "xyes"], [
+            AC_MSG_ERROR([Testing enabled but could not find gmock/gmock.h])
+        ])
+    ])
+    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([--enable-oe-sdk], [Link testcases absolutely against OE SDK so they can be ran within it.])
diff --git a/test/Makefile.am b/test/Makefile.am
index 20ddf2f..4e99de1 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -1,15 +1,12 @@
 AM_CPPFLAGS = \
-    -I$(top_srcdir) \
-    $(PTHREAD_CPPFLAGS)
+    -I$(top_srcdir)
 
 AM_CFLAGS = \
-    $(PTHREAD_CFLAGS) \
     $(SDBUSPLUS_CFLAGS) \
     $(PHOSPHOR_DBUS_INTERFACES_CFLAGS) \
     $(PHOSPHOR_LOGGING_CFLAGS)
 
-AM_CXXFLAGS = \
-    $(PTHREAD_CXXFLAGS)
+AM_CXXFLAGS =
 
 AM_LDFLAGS = \
     -lstdc++fs \
@@ -17,7 +14,8 @@
     $(PHOSPHOR_DBUS_INTERFACES_LIBS) \
     $(PHOSPHOR_LOGGING_LIBS) \
     $(OPENSSL_LIBS) \
-    -lgtest -lgtest_main -lgmock $(PTHREAD_CFLAGS) $(OESDK_TESTCASE_FLAGS)
+    $(GTEST_LIBS) $(GMOCK_LIBS) -lgmock_main
+    $(OESDK_TESTCASE_FLAGS)
 
 check_PROGRAMS =