GL: unify tests for Shader/ShaderProgram compile/link failures.

In particular, test also output of the non-async variant.

src/Magnum/GL/Test/AbstractShaderProgramGLTest.cpp

@@ -485,6 +485,7 @@ void AbstractShaderProgramGLTest::linkFailure() {
         , Shader::Type::Fragment);
     shader.addSource("[fu] bleh error #:! stuff\n");
 
+    /* The compilation should fail */
     {
         Error redirectError{nullptr};
         CORRADE_VERIFY(!shader.compile());
@@ -492,10 +493,19 @@ void AbstractShaderProgramGLTest::linkFailure() {
 
     MyPublicShader program;
     program.attachShaders({shader});
+
+    /* And thus linking as well, saying something like "error: linking with
+       uncompiled/unspecialized shader" */
+    std::ostringstream out;
+    {
+        Error redirectError{&out};
         CORRADE_VERIFY(!program.link());
+    }
 
     Utility::System::sleep(200);
     CORRADE_VERIFY(program.isLinkFinished());
+    CORRADE_COMPARE_AS(out.str(), "GL::AbstractShaderProgram::link(): linking failed with the following message:",
+        TestSuite::Compare::StringHasPrefix);
 }
 
 void AbstractShaderProgramGLTest::linkFailureAsync() {
@@ -512,6 +522,7 @@ void AbstractShaderProgramGLTest::linkFailureAsync() {
         , Shader::Type::Fragment);
     shader.addSource("[fu] bleh error #:! stuff\n");
 
+    /* The compilation should fail */
     {
         Error redirectError{nullptr};
         CORRADE_VERIFY(!shader.compile());
@@ -520,16 +531,24 @@ void AbstractShaderProgramGLTest::linkFailureAsync() {
     MyPublicShader program;
     program.attachShaders({shader});
 
+    /* The link submission should not print anything ... */
     std::ostringstream out;
+    {
         Error redirectError{&out};
         program.submitLink();
+    }
 
     while(!program.isLinkFinished())
         Utility::System::sleep(100);
 
     CORRADE_VERIFY(out.str().empty());
 
+    /* ... only the final check should. In this case it's "error: linking with
+       uncompiled/unspecialized shader" as well. */
+    {
+        Error redirectError{&out};
         CORRADE_VERIFY(!program.checkLink());
+    }
     CORRADE_VERIFY(program.isLinkFinished());
     CORRADE_COMPARE_AS(out.str(), "GL::AbstractShaderProgram::link(): linking failed with the following message:",
         TestSuite::Compare::StringHasPrefix);

src/Magnum/GL/Test/ShaderGLTest.cpp

@@ -58,9 +58,9 @@ struct ShaderGLTest: OpenGLTester {
     void addSourceNoVersion();
     void addFile();
     void compile();
-    void compileFailure();
     void compileAsync();
-    void compileAsyncFailure();
+    void compileFailure();
+    void compileFailureAsync();
     void compileUtf8();
     void compileNoVersion();
 };
@@ -78,9 +78,9 @@ ShaderGLTest::ShaderGLTest() {
               &ShaderGLTest::addSourceNoVersion,
               &ShaderGLTest::addFile,
               &ShaderGLTest::compile,
-              &ShaderGLTest::compileFailure,
               &ShaderGLTest::compileAsync,
-              &ShaderGLTest::compileAsyncFailure,
+              &ShaderGLTest::compileFailure,
+              &ShaderGLTest::compileFailureAsync,
               &ShaderGLTest::compileUtf8,
               &ShaderGLTest::compileNoVersion});
 }
@@ -290,7 +290,7 @@ void ShaderGLTest::compile() {
     CORRADE_VERIFY(shader.isCompileFinished());
 }
 
-void ShaderGLTest::compileFailure() {
+void ShaderGLTest::compileAsync() {
     #ifndef MAGNUM_TARGET_GLES
     constexpr Version v =
         #ifndef CORRADE_TARGET_APPLE
@@ -304,13 +304,17 @@ void ShaderGLTest::compileFailure() {
     #endif
 
     Shader shader(v, Shader::Type::Fragment);
-    shader.addSource("[fu] bleh error #:! stuff\n");
+    shader.addSource("void main() {}\n");
+    shader.submitCompile();
 
-    CORRADE_VERIFY(!shader.compile());
+    while(!shader.isCompileFinished())
+        Utility::System::sleep(100);
+
+    CORRADE_VERIFY(shader.checkCompile());
     CORRADE_VERIFY(shader.isCompileFinished());
 }
 
-void ShaderGLTest::compileAsync() {
+void ShaderGLTest::compileFailure() {
     #ifndef MAGNUM_TARGET_GLES
     constexpr Version v =
         #ifndef CORRADE_TARGET_APPLE
@@ -323,18 +327,20 @@ void ShaderGLTest::compileAsync() {
     constexpr Version v = Version::GLES200;
     #endif
 
-    Shader shader(v, Shader::Type::Fragment);
-    shader.addSource("void main() {}\n");
-    shader.submitCompile();
-
-    while(!shader.isCompileFinished())
-        Utility::System::sleep(100);
+    Shader shader(v, Shader::Type::Vertex);
+    shader.addSource("[fu] bleh error #:! stuff\n");
 
-    CORRADE_VERIFY(shader.checkCompile());
+    std::ostringstream out;
+    {
+        Error redirectError{&out};
+        CORRADE_VERIFY(!shader.compile());
+    }
     CORRADE_VERIFY(shader.isCompileFinished());
+    CORRADE_COMPARE_AS(out.str(), "GL::Shader::compile(): compilation of vertex shader failed with the following message:",
+        TestSuite::Compare::StringHasPrefix);
 }
 
-void ShaderGLTest::compileAsyncFailure() {
+void ShaderGLTest::compileFailureAsync() {
     #ifndef MAGNUM_TARGET_GLES
     constexpr Version v =
         #ifndef CORRADE_TARGET_APPLE
@@ -350,16 +356,23 @@ void ShaderGLTest::compileAsyncFailure() {
     Shader shader(v, Shader::Type::Fragment);
     shader.addSource("[fu] bleh error #:! stuff\n");
 
+    /* The compile submission should not print anything ... */
     std::ostringstream out;
+    {
         Error redirectError{&out};
         shader.submitCompile();
+    }
 
     while(!shader.isCompileFinished())
         Utility::System::sleep(100);
 
     CORRADE_VERIFY(out.str().empty());
 
+    /* ... only the final check should */
+    {
+        Error redirectError{&out};
         CORRADE_VERIFY(!shader.checkCompile());
+    }
     CORRADE_VERIFY(shader.isCompileFinished());
     CORRADE_COMPARE_AS(out.str(), "GL::Shader::compile(): compilation of fragment shader failed with the following message:",
         TestSuite::Compare::StringHasPrefix);