rearrange tests and make more robust

test/fixtures/main.cpp

@@ -0,0 +1,33 @@
+#include "util.hpp"
+
+#include <libgen.h>
+
+std::string baseDirectory;
+
+namespace mbgl {
+namespace test {
+
+const std::string &getBaseDirectory() {
+    return baseDirectory;
+}
+
+}
+}
+
+GTEST_API_ int main(int argc, char *argv[]) {
+    // Note: glibc's dirname() **modifies** the argument and can't handle static strings.
+    std::string file { __FILE__ };
+    file = dirname(const_cast<char *>(file.c_str()));
+    if (file[0] == '/') {
+        // If __FILE__ is an absolute path, we don't have to guess from the argv 0.
+        baseDirectory = file + "/..";
+    } else {
+        std::string argv0 { argv[0] }; argv0 = dirname(const_cast<char *>(argv0.c_str()));
+        baseDirectory = argv0 + "/" + file + "/..";
+    }
+
+    fprintf(stderr, "basedir: %s\n", mbgl::test::getBaseDirectory().c_str());
+
+    testing::InitGoogleTest(&argc, argv);
+    return RUN_ALL_TESTS();
+}