[build] Make test/util.hpp a public interface

We will build the tests as a library and platforms will
provide the test runner.

test/include/mbgl/test/util.hpp

@@ -0,0 +1,78 @@
+#pragma once
+
+#ifdef __APPLE__
+#include <TargetConditionals.h>
+#endif
+
+#if ANDROID
+    #define TEST_READ_ONLY 0
+    #undef TEST_HAS_SERVER
+    #define TEST_HAS_SERVER 0
+#elif TARGET_OS_IOS
+    #define TEST_READ_ONLY 1
+    #undef TEST_HAS_SERVER
+    #define TEST_HAS_SERVER 0
+#else
+    #define TEST_READ_ONLY 0
+    #ifndef TEST_HAS_SERVER
+        #define TEST_HAS_SERVER 1
+    #endif
+#endif
+
+#if TARGET_OS_SIMULATOR
+    #define TEST_IS_SIMULATOR 1
+#else
+    #define TEST_IS_SIMULATOR 0
+#endif
+
+#if !TEST_IS_SIMULATOR && !CI_BUILD
+#define TEST_REQUIRES_ACCURATE_TIMING(name) name
+#else
+#define TEST_REQUIRES_ACCURATE_TIMING(name) DISABLED_ ## name
+#endif
+
+#if !TEST_READ_ONLY
+#define TEST_REQUIRES_WRITE(name) name
+#else
+#define TEST_REQUIRES_WRITE(name) DISABLED_ ## name
+#endif
+
+#if TEST_HAS_SERVER
+#define TEST_REQUIRES_SERVER(name) name
+#else
+#define TEST_REQUIRES_SERVER(name) DISABLED_ ## name
+#endif
+
+#if !CI_BUILD
+#define TEST_DISABLED_ON_CI(name) name
+#else
+#define TEST_DISABLED_ON_CI(name) DISABLED_ ## name
+#endif
+
+#include <mbgl/util/image.hpp>
+#include <mbgl/util/chrono.hpp>
+
+#include <cstdint>
+#include <memory>
+
+#include <gtest/gtest.h>
+
+namespace mbgl {
+namespace test {
+
+class Server {
+public:
+    Server(const char* script);
+    ~Server();
+
+private:
+    int fd = -1;
+};
+
+void checkImage(const std::string& base,
+                const PremultipliedImage& actual,
+                double imageThreshold = 0,
+                double pixelThreshold = 0);
+
+} // namespace test
+} // namespace mbgl