GL: add unit test for Platform::GLContext{NoCreate, ...}

src/Magnum/GL/Test/ContextTest.cpp

@@ -34,6 +34,7 @@ namespace Magnum { namespace GL { namespace Test { namespace {
 struct ContextTest: TestSuite::Tester {
     explicit ContextTest();
 
+    void constructNoCreate();
     void constructCopyMove();
 
     void extensions();
@@ -46,7 +47,8 @@ struct ContextTest: TestSuite::Tester {
 };
 
 ContextTest::ContextTest() {
-    addTests({&ContextTest::constructCopyMove,
+    addTests({&ContextTest::constructNoCreate,
+              &ContextTest::constructCopyMove,
 
               &ContextTest::extensions,
 
@@ -57,6 +59,20 @@ ContextTest::ContextTest() {
               &ContextTest::debugDetectedDrivers});
 }
 
+void ContextTest::constructNoCreate() {
+    {
+        /* Shouldn't crash during construction, shouldn't attempt to access GL,
+           shouldn't crash when destructing */
+        struct MyContext: Context {
+            explicit MyContext(): Context{NoCreate, 0, nullptr, nullptr} {}
+        } context;
+
+        CORRADE_VERIFY(!Context::hasCurrent());
+    }
+
+    CORRADE_VERIFY(!Context::hasCurrent());
+}
+
 void ContextTest::constructCopyMove() {
     /* Only move-construction allowed */
     CORRADE_VERIFY(!(std::is_constructible<Context, const Context&>{}));