No need to install static test libraries on Windows.

src/Magnum/CMakeLists.txt

@@ -270,7 +270,7 @@ if(BUILD_TESTS)
 
     # On Windows we need to install first and then run the tests to avoid "DLL
     # not found" hell, thus we need to install this too
-    if(CORRADE_TARGET_WINDOWS AND NOT CMAKE_CROSSCOMPILING)
+    if(CORRADE_TARGET_WINDOWS AND NOT CMAKE_CROSSCOMPILING AND NOT BUILD_STATIC)
         install(TARGETS MagnumMathTestLib
             RUNTIME DESTINATION ${MAGNUM_BINARY_INSTALL_DIR}
             LIBRARY DESTINATION ${MAGNUM_LIBRARY_INSTALL_DIR}

src/Magnum/MeshTools/CMakeLists.txt

@@ -96,7 +96,7 @@ if(BUILD_TESTS)
 
     # On Windows we need to install first and then run the tests to avoid "DLL
     # not found" hell, thus we need to install this too
-    if(CORRADE_TARGET_WINDOWS AND NOT CMAKE_CROSSCOMPILING)
+    if(CORRADE_TARGET_WINDOWS AND NOT CMAKE_CROSSCOMPILING AND NOT BUILD_STATIC)
         install(TARGETS MagnumMeshToolsTestLib
             RUNTIME DESTINATION ${MAGNUM_BINARY_INSTALL_DIR}
             LIBRARY DESTINATION ${MAGNUM_LIBRARY_INSTALL_DIR}

src/Magnum/SceneGraph/CMakeLists.txt

@@ -109,7 +109,7 @@ if(BUILD_TESTS)
 
     # On Windows we need to install first and then run the tests to avoid "DLL
     # not found" hell, thus we need to install this too
-    if(CORRADE_TARGET_WINDOWS AND NOT CMAKE_CROSSCOMPILING)
+    if(CORRADE_TARGET_WINDOWS AND NOT CMAKE_CROSSCOMPILING AND NOT BUILD_STATIC)
         install(TARGETS MagnumSceneGraphTestLib
             RUNTIME DESTINATION ${MAGNUM_BINARY_INSTALL_DIR}
             LIBRARY DESTINATION ${MAGNUM_LIBRARY_INSTALL_DIR}