diff --git a/src/Magnum/GL/Test/BufferGLTest.cpp b/src/Magnum/GL/Test/BufferGLTest.cpp
index ef6d42202..171fa07fb 100644
--- a/src/Magnum/GL/Test/BufferGLTest.cpp
+++ b/src/Magnum/GL/Test/BufferGLTest.cpp
@@ -34,6 +34,10 @@
 #include "Magnum/GL/Extensions.h"
 #include "Magnum/GL/OpenGLTester.h"
 
+#ifndef MAGNUM_TARGET_GLES2
+#include "Magnum/DebugTools/BufferData.h"
+#endif
+
 #ifndef MAGNUM_TARGET_WEBGL
 #include <Corrade/Containers/String.h>
 #endif
@@ -138,15 +142,14 @@ void BufferGLTest::constructFromData() {
     CORRADE_COMPARE(c.size(), 5*4);
     CORRADE_COMPARE(d.size(), 5*4);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
-    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(a.data()),
+    #ifndef MAGNUM_TARGET_GLES2
+    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(DebugTools::bufferData(a)),
         Containers::arrayView(data),
         TestSuite::Compare::Container);
-    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(b.data()),
+    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(DebugTools::bufferData(b)),
         Containers::arrayView(data),
         TestSuite::Compare::Container);
-    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(c.data()),
+    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(DebugTools::bufferData(c)),
         Containers::arrayView(data),
         TestSuite::Compare::Container);
     /* d's data is undefined, not testing */
@@ -307,10 +310,9 @@ void BufferGLTest::data() {
     MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE(buffer.size(), 5*4);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
     MAGNUM_VERIFY_NO_GL_ERROR();
-    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(buffer.data()),
+    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(DebugTools::bufferData(buffer)),
         Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -320,10 +322,9 @@ void BufferGLTest::data() {
     MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE(buffer.size(), 5*4);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
     MAGNUM_VERIFY_NO_GL_ERROR();
-    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(buffer.data()),
+    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(DebugTools::bufferData(buffer)),
         Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -334,10 +335,9 @@ void BufferGLTest::data() {
     MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE(buffer.size(), 5*4);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
     MAGNUM_VERIFY_NO_GL_ERROR();
-    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(buffer.subData(4, 3*4)),
+    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(DebugTools::bufferSubData(buffer, 4, 3*4)),
         Containers::arrayView(subData),
         TestSuite::Compare::Container);
     #endif
@@ -347,10 +347,9 @@ void BufferGLTest::data() {
     MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE(buffer.size(), 5*4);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
     MAGNUM_VERIFY_NO_GL_ERROR();
-    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(buffer.subData(4, 3*4)),
+    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(DebugTools::bufferSubData(buffer, 4, 3*4)),
         Containers::arrayView(subData),
         TestSuite::Compare::Container);
     #endif
@@ -385,9 +384,8 @@ void BufferGLTest::map() {
     CORRADE_VERIFY(buffer.unmap());
     MAGNUM_VERIFY_NO_GL_ERROR();
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
-    Containers::Array<char> changedContents = buffer.data();
+    #ifndef MAGNUM_TARGET_GLES2
+    Containers::Array<char> changedContents = DebugTools::bufferData(buffer);
     CORRADE_COMPARE(changedContents.size(), 5);
     CORRADE_COMPARE(changedContents[3], 107);
     #endif
@@ -417,9 +415,8 @@ void BufferGLTest::mapRange() {
     CORRADE_VERIFY(buffer.unmap());
     MAGNUM_VERIFY_NO_GL_ERROR();
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
-    Containers::Array<char> changedContents = buffer.data();
+    #ifndef MAGNUM_TARGET_GLES2
+    Containers::Array<char> changedContents = DebugTools::bufferData(buffer);
     CORRADE_COMPARE(changedContents.size(), 5);
     CORRADE_COMPARE(changedContents[4], 107);
     #endif
@@ -457,9 +454,8 @@ void BufferGLTest::mapRangeExplicitFlush() {
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     /* Flushed range should be changed */
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
-    Containers::Array<char> changedContents = buffer.data();
+    #ifndef MAGNUM_TARGET_GLES2
+    Containers::Array<char> changedContents = DebugTools::bufferData(buffer);
     CORRADE_COMPARE(changedContents.size(), 5);
     CORRADE_COMPARE(changedContents[4], 107);
     #endif
@@ -478,9 +474,8 @@ void BufferGLTest::copy() {
     Buffer::copy(buffer1, buffer2, 1, 2, 3);
     MAGNUM_VERIFY_NO_GL_ERROR();
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
-    const Containers::Array<char> subContents = buffer2.subData(2, 3);
+    #ifndef MAGNUM_TARGET_GLES2
+    const Containers::Array<char> subContents = DebugTools::bufferSubData(buffer2, 2, 3);
     CORRADE_COMPARE_AS(subContents, Containers::arrayView(data).slice(1, 4),
         TestSuite::Compare::Container);
     #endif
diff --git a/src/Magnum/GL/Test/BufferImageGLTest.cpp b/src/Magnum/GL/Test/BufferImageGLTest.cpp
index 915f48587..74691ce70 100644
--- a/src/Magnum/GL/Test/BufferImageGLTest.cpp
+++ b/src/Magnum/GL/Test/BufferImageGLTest.cpp
@@ -33,6 +33,10 @@
 #include "Magnum/GL/PixelFormat.h"
 #include "Magnum/GL/OpenGLTester.h"
 
+#ifndef MAGNUM_TARGET_GLES2
+#include "Magnum/DebugTools/BufferData.h"
+#endif
+
 namespace Magnum { namespace GL { namespace Test { namespace {
 
 struct BufferImageGLTest: OpenGLTester {
@@ -98,10 +102,6 @@ void BufferImageGLTest::construct() {
     BufferImage2D a{PixelStorage{}.setAlignment(1),
         PixelFormat::Red, PixelType::UnsignedByte, {1, 3}, data, BufferUsage::StaticDraw};
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     CORRADE_COMPARE(a.storage().alignment(), 1);
@@ -110,8 +110,9 @@ void BufferImageGLTest::construct() {
     CORRADE_COMPARE(a.size(), Vector2i(1, 3));
     CORRADE_COMPARE(a.dataSize(), 3);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -122,10 +123,6 @@ void BufferImageGLTest::constructGeneric() {
     BufferImage2D a{PixelStorage{}.setAlignment(1),
         Magnum::PixelFormat::R8Unorm, {1, 3}, data, BufferUsage::StaticDraw};
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     CORRADE_COMPARE(a.storage().alignment(), 1);
@@ -134,8 +131,9 @@ void BufferImageGLTest::constructGeneric() {
     CORRADE_COMPARE(a.size(), Vector2i(1, 3));
     CORRADE_COMPARE(a.dataSize(), 3);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -150,10 +148,6 @@ void BufferImageGLTest::constructCompressed() {
         CompressedPixelFormat::RGBAS3tcDxt1,
         {4, 4}, data, BufferUsage::StaticDraw};
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     #ifndef MAGNUM_TARGET_GLES
@@ -163,8 +157,9 @@ void BufferImageGLTest::constructCompressed() {
     CORRADE_COMPARE(a.size(), Vector2i(4, 4));
     CORRADE_COMPARE(a.dataSize(), 8);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -179,10 +174,6 @@ void BufferImageGLTest::constructCompressedGeneric() {
         Magnum::CompressedPixelFormat::Bc1RGBAUnorm,
         {4, 4}, data, BufferUsage::StaticDraw};
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     #ifndef MAGNUM_TARGET_GLES
@@ -192,8 +183,9 @@ void BufferImageGLTest::constructCompressedGeneric() {
     CORRADE_COMPARE(a.size(), Vector2i(4, 4));
     CORRADE_COMPARE(a.dataSize(), 8);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -208,10 +200,6 @@ void BufferImageGLTest::constructBuffer() {
     BufferImage2D a{PixelStorage{}.setAlignment(1),
         PixelFormat::Red, PixelType::UnsignedByte, {1, 3}, std::move(buffer), sizeof(data)};
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     CORRADE_VERIFY(!buffer.id());
@@ -222,8 +210,9 @@ void BufferImageGLTest::constructBuffer() {
     CORRADE_COMPARE(a.size(), Vector2i(1, 3));
     CORRADE_COMPARE(a.dataSize(), 3);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -238,10 +227,6 @@ void BufferImageGLTest::constructBufferGeneric() {
     BufferImage2D a{PixelStorage{}.setAlignment(1),
         Magnum::PixelFormat::R8Unorm, {1, 3}, std::move(buffer), sizeof(data)};
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     CORRADE_VERIFY(!buffer.id());
@@ -252,8 +237,9 @@ void BufferImageGLTest::constructBufferGeneric() {
     CORRADE_COMPARE(a.size(), Vector2i(1, 3));
     CORRADE_COMPARE(a.dataSize(), 3);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -272,10 +258,6 @@ void BufferImageGLTest::constructBufferCompressed() {
         CompressedPixelFormat::RGBAS3tcDxt1,
         {4, 4}, std::move(buffer), sizeof(data)};
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     #ifndef MAGNUM_TARGET_GLES
@@ -287,8 +269,9 @@ void BufferImageGLTest::constructBufferCompressed() {
     CORRADE_COMPARE(a.size(), Vector2i(4, 4));
     CORRADE_COMPARE(a.dataSize(), 8);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -307,10 +290,6 @@ void BufferImageGLTest::constructBufferCompressedGeneric() {
         Magnum::CompressedPixelFormat::Bc1RGBAUnorm,
         {4, 4}, std::move(buffer), sizeof(data)};
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     #ifndef MAGNUM_TARGET_GLES
@@ -322,8 +301,9 @@ void BufferImageGLTest::constructBufferCompressedGeneric() {
     CORRADE_COMPARE(a.size(), Vector2i(4, 4));
     CORRADE_COMPARE(a.dataSize(), 8);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -487,10 +467,6 @@ void BufferImageGLTest::setData() {
     const UnsignedShort data2[2*4] = { 1, 2, 3, 4, 5, 6, 7, 8 };
     a.setData(PixelFormat::RGBA, PixelType::UnsignedShort, {1, 2}, data2, BufferUsage::StaticDraw);
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     CORRADE_COMPARE(a.storage().alignment(), 4);
@@ -499,8 +475,9 @@ void BufferImageGLTest::setData() {
     CORRADE_COMPARE(a.size(), Vector2i(1, 2));
     CORRADE_COMPARE(a.dataSize(), 16);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(Containers::arrayCast<UnsignedShort>(imageData),
         Containers::arrayView(data2),
         TestSuite::Compare::Container);
@@ -515,10 +492,6 @@ void BufferImageGLTest::setDataGeneric() {
     const UnsignedShort data2[2*4] = { 1, 2, 3, 4, 5, 6, 7, 8 };
     a.setData(Magnum::PixelFormat::RGBA16Unorm, {1, 2}, data2, BufferUsage::StaticDraw);
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     CORRADE_COMPARE(a.storage().alignment(), 4);
@@ -527,8 +500,9 @@ void BufferImageGLTest::setDataGeneric() {
     CORRADE_COMPARE(a.size(), Vector2i(1, 2));
     CORRADE_COMPARE(a.dataSize(), 16);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(Containers::arrayCast<UnsignedShort>(imageData),
         Containers::arrayView(data2),
         TestSuite::Compare::Container);
@@ -546,10 +520,6 @@ void BufferImageGLTest::setDataCompressed() {
         #endif
         CompressedPixelFormat::RGBAS3tcDxt3, {8, 4}, data2, BufferUsage::StaticDraw);
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     #ifndef MAGNUM_TARGET_GLES
@@ -559,8 +529,9 @@ void BufferImageGLTest::setDataCompressed() {
     CORRADE_COMPARE(a.size(), Vector2i(8, 4));
     CORRADE_COMPARE(a.dataSize(), 16);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data2),
         TestSuite::Compare::Container);
     #endif
@@ -577,10 +548,6 @@ void BufferImageGLTest::setDataCompressedGeneric() {
         #endif
         Magnum::CompressedPixelFormat::Bc2RGBAUnorm, {8, 4}, data2, BufferUsage::StaticDraw);
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     #ifndef MAGNUM_TARGET_GLES
@@ -590,8 +557,9 @@ void BufferImageGLTest::setDataCompressedGeneric() {
     CORRADE_COMPARE(a.size(), Vector2i(8, 4));
     CORRADE_COMPARE(a.dataSize(), 16);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data2),
         TestSuite::Compare::Container);
     #endif
diff --git a/src/Magnum/GL/Test/CMakeLists.txt b/src/Magnum/GL/Test/CMakeLists.txt
index 5f9a38711..651848fb5 100644
--- a/src/Magnum/GL/Test/CMakeLists.txt
+++ b/src/Magnum/GL/Test/CMakeLists.txt
@@ -75,9 +75,7 @@ if(BUILD_GL_TESTS)
     find_package(Corrade REQUIRED PluginManager)
 
     corrade_add_test(GLAbstractTextureGLTest AbstractTextureGLTest.cpp LIBRARIES MagnumOpenGLTesterTestLib)
-    corrade_add_test(GLBufferGLTest BufferGLTest.cpp LIBRARIES MagnumOpenGLTester)
     corrade_add_test(GLCubeMapTextureGLTest CubeMapTextureGLTest.cpp LIBRARIES MagnumOpenGLTesterTestLib)
-    corrade_add_test(GLFramebufferGLTest FramebufferGLTest.cpp LIBRARIES MagnumOpenGLTesterTestLib)
     corrade_add_test(GLMeshGLTest MeshGLTest.cpp LIBRARIES MagnumOpenGLTesterTestLib)
     corrade_add_test(GLRenderbufferGLTest RenderbufferGLTest.cpp LIBRARIES MagnumOpenGLTester)
     corrade_add_test(GLTextureGLTest TextureGLTest.cpp LIBRARIES MagnumOpenGLTesterTestLib)
@@ -89,6 +87,16 @@ if(BUILD_GL_TESTS)
         ${GLAbstractShaderProgramGLTest_RES}
         LIBRARIES MagnumOpenGLTester)
 
+    corrade_add_test(GLBufferGLTest BufferGLTest.cpp LIBRARIES MagnumOpenGLTester)
+    if(NOT MAGNUM_TARGET_GLES2)
+        target_link_libraries(GLBufferGLTest PRIVATE MagnumDebugTools)
+    endif()
+
+    corrade_add_test(GLFramebufferGLTest FramebufferGLTest.cpp LIBRARIES MagnumOpenGLTesterTestLib)
+    if(NOT MAGNUM_TARGET_GLES2)
+        target_link_libraries(GLFramebufferGLTest PRIVATE MagnumDebugTools)
+    endif()
+
     corrade_add_test(GLContextGLTest ContextGLTest.cpp LIBRARIES MagnumOpenGLTester)
     if(NOT CORRADE_TARGET_EMSCRIPTEN)
         set(THREADS_PREFER_PTHREAD_FLAG TRUE)
@@ -162,10 +170,10 @@ if(BUILD_GL_TESTS)
     endif()
 
     if(NOT MAGNUM_TARGET_GLES2)
-        corrade_add_test(GLBufferImageGLTest BufferImageGLTest.cpp LIBRARIES MagnumOpenGLTesterTestLib)
+        corrade_add_test(GLBufferImageGLTest BufferImageGLTest.cpp LIBRARIES MagnumOpenGLTesterTestLib MagnumDebugTools)
         corrade_add_test(GLPrimitiveQueryGLTest PrimitiveQueryGLTest.cpp LIBRARIES MagnumOpenGLTester)
         corrade_add_test(GLTextureArrayGLTest TextureArrayGLTest.cpp LIBRARIES MagnumOpenGLTester)
-        corrade_add_test(GLTransformFeedbackGLTest TransformFeedbackGLTest.cpp LIBRARIES MagnumOpenGLTester)
+        corrade_add_test(GLTransformFeedbackGLTest TransformFeedbackGLTest.cpp LIBRARIES MagnumOpenGLTester MagnumDebugTools)
     endif()
 
     if(NOT MAGNUM_TARGET_GLES2 AND NOT MAGNUM_TARGET_WEBGL)
diff --git a/src/Magnum/GL/Test/FramebufferGLTest.cpp b/src/Magnum/GL/Test/FramebufferGLTest.cpp
index e8a48276a..14d24611a 100644
--- a/src/Magnum/GL/Test/FramebufferGLTest.cpp
+++ b/src/Magnum/GL/Test/FramebufferGLTest.cpp
@@ -58,6 +58,10 @@
 #include "Magnum/GL/RectangleTexture.h"
 #endif
 
+#ifndef MAGNUM_TARGET_GLES2
+#include "Magnum/DebugTools/BufferData.h"
+#endif
+
 namespace Magnum { namespace GL { namespace Test { namespace {
 
 struct FramebufferGLTest: OpenGLTester {
@@ -1742,9 +1746,9 @@ void FramebufferGLTest::readBuffer() {
     CORRADE_COMPARE(colorImage.size(), Vector2i(8, 16));
 
     MAGNUM_VERIFY_NO_GL_ERROR();
-    /** @todo How to test this on ES? */
-    #ifndef MAGNUM_TARGET_GLES
-    auto colorData = colorImage.buffer().data();
+
+    #ifndef MAGNUM_TARGET_GLES2
+    auto colorData = DebugTools::bufferData(colorImage.buffer());
     CORRADE_COMPARE(colorData.size(), (DataOffset + 8*16)*sizeof(Color4ub));
     CORRADE_COMPARE(Containers::arrayCast<Color4ub>(colorData)[DataOffset], Color4ub(128, 64, 32, 17));
     #endif
diff --git a/src/Magnum/GL/Test/TransformFeedbackGLTest.cpp b/src/Magnum/GL/Test/TransformFeedbackGLTest.cpp
index 25a3b008f..ec2863e53 100644
--- a/src/Magnum/GL/Test/TransformFeedbackGLTest.cpp
+++ b/src/Magnum/GL/Test/TransformFeedbackGLTest.cpp
@@ -24,8 +24,11 @@
 */
 
 #include <tuple>
+#include <Corrade/Containers/Array.h>
 #include <Corrade/Containers/Reference.h>
+#include <Corrade/TestSuite/Compare/Container.h>
 
+#include "Magnum/DebugTools/BufferData.h"
 #include "Magnum/Image.h"
 #include "Magnum/GL/AbstractShaderProgram.h"
 #include "Magnum/GL/Buffer.h"
@@ -307,14 +310,11 @@ void TransformFeedbackGLTest::attachBase() {
 
     MAGNUM_VERIFY_NO_GL_ERROR();
 
-    #ifdef MAGNUM_TARGET_WEBGL
-    CORRADE_SKIP("Can't map buffers on WebGL.");
-    #else
-    auto data = Containers::arrayCast<const Vector2>(output.mapRead(0, 2*sizeof(Vector2)));
-    CORRADE_COMPARE(data[0], Vector2(1.0f, -1.0f));
-    CORRADE_COMPARE(data[1], Vector2(0.0f, 0.0f));
-    output.unmap();
-    #endif
+    auto data = DebugTools::bufferData(output);
+    MAGNUM_VERIFY_NO_GL_ERROR();
+    CORRADE_COMPARE_AS(Containers::arrayCast<Vector2>(data),
+        Containers::arrayView<Vector2>({{1.0f, -1.0f}, {0.0f, 0.0f}}),
+        TestSuite::Compare::Container);
 }
 
 void TransformFeedbackGLTest::attachRange() {
@@ -354,14 +354,11 @@ void TransformFeedbackGLTest::attachRange() {
 
     MAGNUM_VERIFY_NO_GL_ERROR();
 
-    #ifdef MAGNUM_TARGET_WEBGL
-    CORRADE_SKIP("Can't map buffers on WebGL.");
-    #else
-    auto data = Containers::arrayCast<const Vector2>(output.mapRead(256, 2*sizeof(Vector2)));
-    CORRADE_COMPARE(data[0], Vector2(1.0f, -1.0f));
-    CORRADE_COMPARE(data[1], Vector2(0.0f, 0.0f));
-    output.unmap();
-    #endif
+    auto data = DebugTools::bufferSubData(output, 256, 2*sizeof(Vector2));
+    MAGNUM_VERIFY_NO_GL_ERROR();
+    CORRADE_COMPARE_AS(Containers::arrayCast<Vector2>(data),
+        Containers::arrayView<Vector2>({{1.0f, -1.0f}, {0.0f, 0.0f}}),
+        TestSuite::Compare::Container);
 }
 
 struct XfbMultiShader: AbstractShaderProgram {
@@ -445,19 +442,17 @@ void TransformFeedbackGLTest::attachBases() {
 
     MAGNUM_VERIFY_NO_GL_ERROR();
 
-    #ifdef MAGNUM_TARGET_WEBGL
-    CORRADE_SKIP("Can't map buffers on WebGL.");
-    #else
-    auto data1 = Containers::arrayCast<const Vector2>(output1.mapRead(0, 2*sizeof(Vector2)));
-    CORRADE_COMPARE(data1[0], Vector2(1.0f, -1.0f));
-    CORRADE_COMPARE(data1[1], Vector2(0.0f, 0.0f));
-    output1.unmap();
-
-    auto data2 = Containers::arrayCast<const Float>(output2.mapRead(0, 2*sizeof(Float)));
-    CORRADE_COMPARE(data2[0], 0.0f);
-    CORRADE_COMPARE(data2[1], -2.0f);
-    output2.unmap();
-    #endif
+    auto data1 = DebugTools::bufferData(output1);
+    MAGNUM_VERIFY_NO_GL_ERROR();
+    CORRADE_COMPARE_AS(Containers::arrayCast<Vector2>(data1),
+        Containers::arrayView<Vector2>({{1.0f, -1.0f}, {0.0f, 0.0f}}),
+        TestSuite::Compare::Container);
+
+    auto data2 = DebugTools::bufferData(output2);
+    MAGNUM_VERIFY_NO_GL_ERROR();
+    CORRADE_COMPARE_AS(Containers::arrayCast<Float>(data2),
+        Containers::arrayView({0.0f, -2.0f}),
+        TestSuite::Compare::Container);
 }
 
 void TransformFeedbackGLTest::attachRanges() {
@@ -502,19 +497,17 @@ void TransformFeedbackGLTest::attachRanges() {
 
     MAGNUM_VERIFY_NO_GL_ERROR();
 
-    #ifdef MAGNUM_TARGET_WEBGL
-    CORRADE_SKIP("Can't map buffers on WebGL.");
-    #else
-    auto data1 = Containers::arrayCast<const Vector2>(output1.mapRead(256, 2*sizeof(Vector2)));
-    CORRADE_COMPARE(data1[0], Vector2(1.0f, -1.0f));
-    CORRADE_COMPARE(data1[1], Vector2(0.0f, 0.0f));
-    output1.unmap();
-
-    auto data2 = Containers::arrayCast<const Float>(output2.mapRead(512, 2*sizeof(Float)));
-    CORRADE_COMPARE(data2[0], 0.0f);
-    CORRADE_COMPARE(data2[1], -2.0f);
-    output2.unmap();
-    #endif
+    auto data1 = DebugTools::bufferSubData(output1, 256, 2*sizeof(Vector2));
+    MAGNUM_VERIFY_NO_GL_ERROR();
+    CORRADE_COMPARE_AS(Containers::arrayCast<Vector2>(data1),
+        Containers::arrayView<Vector2>({{1.0f, -1.0f}, {0.0f, 0.0f}}),
+        TestSuite::Compare::Container);
+
+    auto data2 = DebugTools::bufferSubData(output2, 512, 2*sizeof(Float));
+    MAGNUM_VERIFY_NO_GL_ERROR();
+    CORRADE_COMPARE_AS(Containers::arrayCast<Float>(data2),
+        Containers::arrayView({0.0f, -2.0f}),
+        TestSuite::Compare::Container);
 }
 
 #ifndef MAGNUM_TARGET_GLES
diff --git a/src/Magnum/Text/Test/CMakeLists.txt b/src/Magnum/Text/Test/CMakeLists.txt
index 9aac7e331..cdf641aa8 100644
--- a/src/Magnum/Text/Test/CMakeLists.txt
+++ b/src/Magnum/Text/Test/CMakeLists.txt
@@ -53,4 +53,7 @@ if(TARGET_GL AND BUILD_GL_TESTS)
     corrade_add_test(TextDistanceFieldGlyphCacheGLTest DistanceFieldGlyphCacheGLTest.cpp LIBRARIES MagnumText MagnumOpenGLTester)
     corrade_add_test(TextGlyphCacheGLTest GlyphCacheGLTest.cpp LIBRARIES MagnumText MagnumOpenGLTester)
     corrade_add_test(TextRendererGLTest RendererGLTest.cpp LIBRARIES MagnumText MagnumOpenGLTester)
+    if(NOT MAGNUM_TARGET_GLES2)
+        target_link_libraries(TextRendererGLTest PRIVATE MagnumDebugTools)
+    endif()
 endif()
diff --git a/src/Magnum/Text/Test/RendererGLTest.cpp b/src/Magnum/Text/Test/RendererGLTest.cpp
index 276f3fbc2..1907d8fcd 100644
--- a/src/Magnum/Text/Test/RendererGLTest.cpp
+++ b/src/Magnum/Text/Test/RendererGLTest.cpp
@@ -32,6 +32,10 @@
 #include "Magnum/Text/AbstractFont.h"
 #include "Magnum/Text/Renderer.h"
 
+#ifndef MAGNUM_TARGET_GLES2
+#include "Magnum/DebugTools/BufferData.h"
+#endif
+
 namespace Magnum { namespace Text { namespace Test { namespace {
 
 struct RendererGLTest: GL::OpenGLTester {
@@ -187,10 +191,9 @@ void RendererGLTest::renderMesh() {
     /* Bounds */
     CORRADE_COMPARE(bounds, Range2D({0.0f, -0.5f}, {5.0f, 1.0f}).translated(offset));
 
-    /** @todo How to verify this on ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
     /* Vertex buffer contents */
-    Containers::Array<char> vertices = vertexBuffer.data();
+    Containers::Array<char> vertices = DebugTools::bufferData(vertexBuffer);
     CORRADE_COMPARE_AS(Containers::arrayCast<const Float>(vertices),
         Containers::arrayView<Float>({
             0.0f + offset.x(),  0.5f + offset.y(), 0.0f, 10.0f,
@@ -208,8 +211,8 @@ void RendererGLTest::renderMesh() {
             5.0f + offset.x(),   1.0f + offset.y(), 18.0f, 10.0f,
             5.0f + offset.x(),  -0.5f + offset.y(), 18.0f,  0.0f
         }), TestSuite::Compare::Container);
-
-    Containers::Array<char> indices = indexBuffer.data();
+    /* Index buffer contents */
+    Containers::Array<char> indices = DebugTools::bufferData(indexBuffer);
     CORRADE_COMPARE_AS(Containers::arrayCast<const UnsignedByte>(indices),
         Containers::arrayView<UnsignedByte>({
             0,  1,  2,  1,  3,  2,
@@ -220,10 +223,11 @@ void RendererGLTest::renderMesh() {
 }
 
 void RendererGLTest::renderMeshIndexType() {
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
     TestFont font;
     GL::Mesh mesh{NoCreate};
-    GL::Buffer vertexBuffer, indexBuffer;
+    GL::Buffer vertexBuffer{GL::Buffer::TargetHint::Array};
+    GL::Buffer indexBuffer{GL::Buffer::TargetHint::ElementArray};
 
     /* Sizes: four vertices per glyph, each vertex has 2D position and 2D
        texture coordinates, each float is four bytes; six indices per glyph. */
@@ -232,7 +236,7 @@ void RendererGLTest::renderMeshIndexType() {
     std::tie(mesh, std::ignore) = Text::Renderer3D::render(font, nullGlyphCache,
         1.0f, std::string(64, 'a'), vertexBuffer, indexBuffer, GL::BufferUsage::StaticDraw);
     MAGNUM_VERIFY_NO_GL_ERROR();
-    Containers::Array<char> indicesByte = indexBuffer.data();
+    Containers::Array<char> indicesByte = DebugTools::bufferData(indexBuffer);
     CORRADE_COMPARE(vertexBuffer.size(), 256*(2 + 2)*4);
     CORRADE_COMPARE(indicesByte.size(), 64*6);
     CORRADE_COMPARE_AS(Containers::arrayCast<const UnsignedByte>(indicesByte).prefix(18),
@@ -246,7 +250,7 @@ void RendererGLTest::renderMeshIndexType() {
     std::tie(mesh, std::ignore) = Text::Renderer3D::render(font, nullGlyphCache,
         1.0f, std::string(65, 'a'), vertexBuffer, indexBuffer, GL::BufferUsage::StaticDraw);
     MAGNUM_VERIFY_NO_GL_ERROR();
-    Containers::Array<char> indicesShort = indexBuffer.data();
+    Containers::Array<char> indicesShort = DebugTools::bufferData(indexBuffer);
     CORRADE_COMPARE(vertexBuffer.size(), 260*(2 + 2)*4);
     CORRADE_COMPARE(indicesShort.size(), 65*6*2);
     CORRADE_COMPARE_AS(Containers::arrayCast<const UnsignedShort>(indicesShort).prefix(18),
@@ -256,7 +260,7 @@ void RendererGLTest::renderMeshIndexType() {
             8,  9, 10,  9, 11, 10
         }), TestSuite::Compare::Container);
     #else
-    CORRADE_SKIP("Can't verify buffer contents on OpenGL ES.");
+    CORRADE_SKIP("Can't verify buffer contents on OpenGL ES 2.0.");
     #endif
 }
 
@@ -280,9 +284,9 @@ void RendererGLTest::mutableText() {
     renderer.reserve(4, GL::BufferUsage::DynamicDraw, GL::BufferUsage::DynamicDraw);
     MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE(renderer.capacity(), 4);
-    /** @todo How to verify this on ES? */
-    #ifndef MAGNUM_TARGET_GLES
-    Containers::Array<char> indices = renderer.indexBuffer().data();
+
+    #ifndef MAGNUM_TARGET_GLES2
+    Containers::Array<char> indices = DebugTools::bufferData(renderer.indexBuffer());
     CORRADE_COMPARE_AS(Containers::arrayCast<const UnsignedByte>(indices).prefix(24),
         Containers::arrayView<UnsignedByte>({
              0,  1,  2,  1,  3,  2,
@@ -301,9 +305,8 @@ void RendererGLTest::mutableText() {
 
     /* Aligned to line/left, no offset needed */
 
-    /** @todo How to verify this on ES? */
-    #ifndef MAGNUM_TARGET_GLES
-    Containers::Array<char> vertices = renderer.vertexBuffer().data();
+    #ifndef MAGNUM_TARGET_GLES2
+    Containers::Array<char> vertices = DebugTools::bufferData(renderer.vertexBuffer());
     CORRADE_COMPARE_AS(Containers::arrayCast<const Float>(vertices).prefix(48),
         Containers::arrayView<Float>({
             0.0f,  0.5f, 0.0f, 10.0f,