Improve ECMAddAppIconMacro.

Summary:
- Add support for SIDEBAR_ICONS on macOS
- Allow specifying a basename for the icon file via OUTFILE_BASENAME
- Add support for HiRes icons on Windows via icotool

I'm sorry this went all into one big change. I see that it's not optimal,
but it's really hard to rip it apart...

Also to me the whole code with support for two flavors of png2ico and icotool seems very spaghetti-ish. IMHO there's no good reason to keep supporting all three, icotool is the only maintained project and the only one supporting more than 128px wide icons. That's why I would suggest to simplify the whole code by only supporting icotool in one of the next releases.

Test Plan:
We use this version of ECMAddAppIconMacro in ownCloud client and it works...
I tested icotool natively and while cross-compiling on linux.

SIDEBAR_ICONS are also working...

If you want to test this with the ownCloud client, it's best to use
https://github.com/dschmidt/owncloud-client/tree/fix-app-icon-macro
because that contains a small fix I just PR'ed and which is not
in master yet. (We maintain a fork of the module there, so compiling it for Windows or macOS will automatically use the version of the module that I'm submitting)

Reviewers: vonreth, vpinon, apol, alexmerry, cgiboudeaux

Reviewed By: cgiboudeaux

Subscribers: cgiboudeaux, kde-frameworks-devel, kde-buildsystem

Tags: #frameworks, #build_system

Differential Revision: https://phabricator.kde.org/D13698

7 files changed, 324 insertions, 81 deletions

diff --git a/docs/find-module/FindIcoTool.rst b/docs/find-module/FindIcoTool.rst
new file mode 100644
index 00000000..ec088a6b
--- /dev/null
+++ b/docs/find-module/FindIcoTool.rst
@@ -0,0 +1 @@
+.. ecm-module:: ../../find-modules/FindIcoTool.cmake
diff --git a/find-modules/FindIcoTool.cmake b/find-modules/FindIcoTool.cmake
new file mode 100644
index 00000000..cf893d62
--- /dev/null
+++ b/find-modules/FindIcoTool.cmake
@@ -0,0 +1,80 @@
+#.rst:
+# FindIcoTool
+# -----------
+#
+# Try to find icotool.
+#
+# If the icotool executable is not in your PATH, you can provide
+# an alternative name or full path location with the ``IcoTool_EXECUTABLE``
+# variable.
+#
+# This will define the following variables:
+#
+# ``IcoTool_FOUND``
+#     True if icotool is available.
+#
+# ``IcoTool_EXECUTABLE``
+#     The icotool executable.
+#
+# If ``IcoTool_FOUND`` is TRUE, it will also define the following imported
+# target:
+#
+# ``IcoTool::IcoTool``
+#     The icotool executable.
+#
+# Since 5.48.
+
+#=============================================================================
+# Copyright 2017 Vincent Pinon <vpinon@kde.org>
+# Copyright 2014 Alex Merry <alex.merry@kde.org>
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+# 3. The name of the author may not be used to endorse or promote products
+#    derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#=============================================================================
+
+include(${CMAKE_CURRENT_LIST_DIR}/ECMFindModuleHelpersStub.cmake)
+ecm_find_package_version_check(IcoTool)
+find_program(IcoTool_EXECUTABLE NAMES icotool)
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(IcoTool
+    FOUND_VAR
+        IcoTool_FOUND
+    REQUIRED_VARS
+        IcoTool_EXECUTABLE
+)
+mark_as_advanced(IcoTool_EXECUTABLE)
+
+if (IcoTool_FOUND)
+    if (NOT TARGET IcoTool::IcoTool)
+        add_executable(IcoTool::IcoTool IMPORTED)
+        set_target_properties(IcoTool::IcoTool PROPERTIES
+            IMPORTED_LOCATION "${IcoTool_EXECUTABLE}"
+        )
+    endif()
+endif()
+
+include(FeatureSummary)
+set_package_properties(IcoTool PROPERTIES
+    URL "http://www.nongnu.org/icoutils/"
+    DESCRIPTION "Executable that converts a collection of PNG files into a Windows icon file"
+)
diff --git a/modules/ECMAddAppIcon.cmake b/modules/ECMAddAppIcon.cmake
index 3e609d34..87be864c 100644
--- a/modules/ECMAddAppIcon.cmake
+++ b/modules/ECMAddAppIcon.cmake
@@ -7,7 +7,10 @@
 # ::
 #
 #  ecm_add_app_icon(<sources_var>
-#                   ICONS <icon> [<icon> [...]])
+#                   ICONS <icon> [<icon> [...]]
+#                   [SIDEBAR_ICONS <icon> [<icon> [...]] # Since 5.48
+#                   [OUTFILE_BASENAME <name>]) # Since 5.48
+#                   )
 #
 # The given icons, whose names must match the pattern::
 #
@@ -22,12 +25,23 @@
 # ``<other_text>`` can be any other text. See the platform notes below for any
 # recommendations about icon sizes.
 #
+# ``SIDEBAR_ICONS`` can be used to add Mac OS X sidebar
+# icons to the generated iconset. They are used when a folder monitored by the
+# application is dragged into Finder's sidebar. Since 5.48.
+#
+# ``OUTFILE_BASENAME`` will be used as the basename for the icon file. If
+# you specify it, the icon file will be called ``<OUTFILE_BASENAME>.icns`` on Mac OS X
+# and ``<OUTFILE_BASENAME>.ico`` on Windows. If you don't specify it, it defaults
+# to ``<sources_var>.<ext>``. Since 5.48.
+#
+#
 # Windows notes
 #    * Icons are compiled into the executable using a resource file.
 #    * Icons may not show up in Windows Explorer if the executable
 #      target does not have the ``WIN32_EXECUTABLE`` property set.
-#    * The tool png2ico is required. See :find-module:`FindPng2Ico`.
-#    * Supported sizes: 16, 32, 48, 64, 128.
+#    * One of the tools png2ico (See :find-module:`FindPng2Ico`) or
+#      icotool (see :find-module:`FindIcoTool`) is required.
+#    * Supported sizes: 16, 24, 32, 48, 64, 128, 256, 512 and 1024.
 #
 # Mac OS X notes
 #    * The executable target must have the ``MACOSX_BUNDLE`` property set.
@@ -42,14 +56,18 @@
 #      "Retina" (high-resolution) displays. For example, a 32px icon, if
 #      provided, will be used as a 32px icon on standard-resolution displays,
 #      and as a 16px-equivalent icon (with an "@2x" tag) on high-resolution
-#      displays. ksvg2icns handles this internally.
+#      displays. That is why you should provide 64px and 1024px icons although
+#      they are not supported anymore directly. Instead they will be used as
+#      32px@2x and 512px@2x. ksvg2icns handles this internally.
 #    * This function sets the ``MACOSX_BUNDLE_ICON_FILE`` variable to the name
 #      of the generated icns file, so that it will be used as the
 #      ``MACOSX_BUNDLE_ICON_FILE`` target property when you call
 #      ``add_executable``.
+#    * Sidebar icons should typically provided in 16, 32, 64, 128 and 256px.
 #
 # Since 1.7.0.
 
+
 #=============================================================================
 # Copyright 2014 Alex Merry <alex.merry@kde.org>
 # Copyright 2014 Ralf Habacker <ralf.habacker@freenet.de>
@@ -84,8 +102,8 @@ include(CMakeParseArguments)
 
 function(ecm_add_app_icon appsources)
     set(options)
-    set(oneValueArgs)
-    set(multiValueArgs ICONS)
+    set(oneValueArgs OUTFILE_BASENAME)
+    set(multiValueArgs ICONS SIDEBAR_ICONS)
     cmake_parse_arguments(ARG "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
 
     if(NOT ARG_ICONS)
@@ -120,82 +138,70 @@ function(ecm_add_app_icon appsources)
         endforeach()
     endif()
 
-    set(known_sizes 16 32 48 64 128 256 512 1024)
-    foreach(size ${known_sizes})
-        set(icons_at_${size}px)
-    endforeach()
 
-    foreach(icon ${ARG_ICONS})
-        get_filename_component(icon_full ${icon} ABSOLUTE)
-        if (NOT EXISTS "${icon_full}")
-            message(AUTHOR_WARNING "${icon_full} does not exist, ignoring")
-        else()
-            get_filename_component(icon_name ${icon} NAME)
-            string(REGEX MATCH "([0-9]+)\\-[^/]+\\.([a-z]+)$"
-                               _dummy "${icon_name}")
-            set(size  "${CMAKE_MATCH_1}")
-            set(ext   "${CMAKE_MATCH_2}")
-            if (NOT (ext STREQUAL "svg" OR ext STREQUAL "svgz"))
-                if (NOT size)
-                    message(AUTHOR_WARNING "${icon_full} is not named correctly for ecm_add_app_icon - ignoring")
-                elseif (NOT ext STREQUAL "png")
-                    message(AUTHOR_WARNING "${icon_full} is not a png file - ignoring")
-                else()
-                    list(FIND known_sizes "${size}" offset)
-                    if (offset GREATER -1)
-                        list(APPEND icons_at_${size}px "${icon_full}")
-                    endif()
-                endif()
-            endif()
-        endif()
-    endforeach()
+    _ecm_add_app_icon_categorize_icons("${ARG_ICONS}" "icons" "16;24;32;48;64;128;256;512;1024")
+    if(ARG_SIDEBAR_ICONS)
+        _ecm_add_app_icon_categorize_icons("${ARG_SIDEBAR_ICONS}" "sidebar_icons" "16;32;64;128;256")
+    endif()
 
-    set(mac_icons ${icons_at_16px}
+    set(mac_icons
+                  # Icons: https://developer.apple.com/library/content/documentation/GraphicsAnimation/Conceptual/HighResolutionOSX/Optimizing/Optimizing.html#//apple_ref/doc/uid/TP40012302-CH7-SW4
+                  ${icons_at_16px}
                   ${icons_at_32px}
                   ${icons_at_64px}
                   ${icons_at_128px}
                   ${icons_at_256px}
                   ${icons_at_512px}
                   ${icons_at_1024px})
-    if (NOT icons_at_128px)
-        message(AUTHOR_WARNING "No 128px icon provided; this will not work on Mac OS X")
+
+    set(mac_sidebar_icons
+                  # Sidebar Icons: https://developer.apple.com/library/content/documentation/General/Conceptual/ExtensibilityPG/Finder.html#//apple_ref/doc/uid/TP40014214-CH15-SW15
+                  ${sidebar_icons_at_16px}
+                  ${sidebar_icons_at_32px}
+                  ${sidebar_icons_at_64px}
+                  ${sidebar_icons_at_128px}
+                  ${sidebar_icons_at_256px})
+
+    if (NOT (mac_icons OR mac_sidebar_icons))
+        message(AUTHOR_WARNING "No icons suitable for use on macOS provided")
     endif()
 
-    set(windows_icons ${icons_at_16px}
-                      ${icons_at_32px}
-                      ${icons_at_48px}
-                      ${icons_at_64px}
-                      ${icons_at_128px})
-    if (NOT windows_icons)
+
+    set(windows_icons_classic ${icons_at_16px}
+                              ${icons_at_24px}
+                              ${icons_at_32px}
+                              ${icons_at_48px}
+                              ${icons_at_64px}
+                              ${icons_at_128px})
+    set(windows_icons_modern  ${windows_icons_classic}
+                              ${icons_at_256px}
+                              ${icons_at_512px}
+                              ${icons_at_1024px})
+
+    if (NOT (windows_icons_modern OR windows_icons_classic))
         message(AUTHOR_WARNING "No icons suitable for use on Windows provided")
     endif()
 
-    set (_outfilename "${CMAKE_CURRENT_BINARY_DIR}/${appsources}")
+    if (ARG_OUTFILE_BASENAME)
+        set (_outfilebasename "${ARG_OUTFILE_BASENAME}")
+    else()
+        set (_outfilebasename "${appsources}")
+    endif()
+    set (_outfilename "${CMAKE_CURRENT_BINARY_DIR}/${_outfilebasename}")
 
-    if (WIN32 AND windows_icons)
+    if (WIN32 AND (windows_icons_modern OR windows_icons_classic))
         set(saved_CMAKE_MODULE_PATH "${CMAKE_MODULE_PATH}")
         set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${ECM_FIND_MODULE_DIR})
         find_package(Png2Ico)
+        find_package(IcoTool)
         set(CMAKE_MODULE_PATH "${saved_CMAKE_MODULE_PATH}")
 
-        if (Png2Ico_FOUND)
-            if (Png2Ico_HAS_RCFILE_ARGUMENT)
-                add_custom_command(
-                    OUTPUT "${_outfilename}.rc" "${_outfilename}.ico"
-                    COMMAND Png2Ico::Png2Ico
-                    ARGS
-                        --rcfile "${_outfilename}.rc"
-                        "${_outfilename}.ico"
-                        ${windows_icons}
-                    DEPENDS ${windows_icons}
-                    WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
-                )
-            else()
+        function(create_windows_icon_and_rc command args deps)
                 add_custom_command(
                     OUTPUT "${_outfilename}.ico"
-                    COMMAND Png2Ico::Png2Ico
-                    ARGS "${_outfilename}.ico" ${windows_icons}
-                    DEPENDS ${windows_icons}
+                    COMMAND ${command}
+                    ARGS ${args}
+                    DEPENDS ${deps}
                     WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
                 )
                 # this bit's a little hacky to make the dependency stuff work
@@ -207,12 +213,67 @@ function(ecm_add_app_icon appsources)
                     DEPENDS "${_outfilename}.ico"
                     WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}"
                 )
-            endif()
+        endfunction()
+
+        if (IcoTool_FOUND)
+            list(APPEND icotool_args "-c" "-o" "${_outfilename}.ico")
+
+            # According to https://stackoverflow.com/a/40851713/2886832
+            # Windows always chooses the first icon above 255px, all other ones will be ignored
+            set(maxSize 0)
+            foreach(size 256 512 1024)
+                if(icons_at_${size}px)
+                    set(maxSize "${size}")
+                endif()
+            endforeach()
+
+            foreach(size 16 24 32 48 64 128 ${maxSize})
+                if(NOT icons_at_${size}px)
+                    continue()
+                endif()
+
+                set(icotool_icon_arg "")
+                if(size STREQUAL "${maxSize}")
+                    # maxSize icon needs to be included as raw png
+                    list(APPEND icotool_args "-r")
+                endif()
+
+                foreach(icon ${icons_at_${size}px})
+                    list(APPEND icotool_args "${icons_at_${size}px}")
+                endforeach()
+            endforeach()
+
+            create_windows_icon_and_rc(IcoTool::IcoTool "${icotool_args}" "${windows_icons_modern}")
+            set(${appsources} "${${appsources}};${_outfilename}.rc" PARENT_SCOPE)
+
+        # standard png2ico has no rcfile argument
+        elseif(Png2Ico_FOUND AND NOT Png2Ico_HAS_RCFILE_ARGUMENT AND windows_icons_classic)
+            set(png2ico_args)
+            list(APPEND png2ico_args "${_outfilename}.ico")
+            list(APPEND png2ico_args "${windows_icons_classic}")
+
+            create_windows_icon_and_rc(Png2Ico::Png2Ico "${png2ico_args}" "${windows_icons_classic}")
             set(${appsources} "${${appsources}};${_outfilename}.rc" PARENT_SCOPE)
+
+        # png2ico from kdewin provides rcfile argument
+        elseif(Png2Ico_FOUND AND windows_icons_classic)
+            add_custom_command(
+                  OUTPUT "${_outfilename}.rc" "${_outfilename}.ico"
+                  COMMAND Png2Ico::Png2Ico
+                  ARGS
+                      --rcfile "${_outfilename}.rc"
+                      "${_outfilename}.ico"
+                      ${windows_icons_classic}
+                  DEPENDS ${windows_icons_classic}
+                  WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
+              )
+
+            set(${appsources} "${${appsources}};${_outfilename}.rc" PARENT_SCOPE)
+        # else none of the supported tools was found
         else()
-            message(WARNING "Unable to find the png2ico utility - application will not have an application icon!")
+            message(WARNING "Unable to find the png2ico or icotool utilities or icons in matching sizes - application will not have an application icon!")
         endif()
-    elseif (APPLE AND mac_icons)
+    elseif (APPLE AND (mac_icons OR mac_sidebar_icons))
         # first generate .iconset directory structure, then convert to .icns format using the Mac OS X "iconutil" utility,
         # to create retina compatible icon, you need png source files in pixel resolution 16x16, 32x32, 64x64, 128x128,
         # 256x256, 512x512, 1024x1024
@@ -224,31 +285,55 @@ function(ecm_add_app_icon appsources)
                 ARGS -E make_directory "${_outfilename}.iconset"
             )
             set(iconset_icons)
-            macro(copy_icon filename sizename)
+            macro(copy_icon filename sizename type)
                 add_custom_command(
-                    OUTPUT "${_outfilename}.iconset/icon_${sizename}.png"
+                    OUTPUT "${_outfilename}.iconset/${type}_${sizename}.png"
                     COMMAND ${CMAKE_COMMAND}
                     ARGS -E copy
                          "${filename}"
-                         "${_outfilename}.iconset/icon_${sizename}.png"
+                         "${_outfilename}.iconset/${type}_${sizename}.png"
                     DEPENDS
                         "${_outfilename}.iconset"
                         "${filename}"
                     WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
                 )
                 list(APPEND iconset_icons
-                            "${_outfilename}.iconset/icon_${sizename}.png")
+                        "${_outfilename}.iconset/${type}_${sizename}.png")
             endmacro()
-            foreach(size 16 32 64 128 256 512)
+
+            # List of supported sizes and filenames taken from:
+            # https://developer.apple.com/library/content/documentation/GraphicsAnimation/Conceptual/HighResolutionOSX/Optimizing/Optimizing.html#//apple_ref/doc/uid/TP40012302-CH7-SW4
+            foreach(size 16 32 128 256 512)
                 math(EXPR double_size "2 * ${size}")
                 foreach(file ${icons_at_${size}px})
-                    copy_icon("${file}" "${size}x${size}")
+                    copy_icon("${file}" "${size}x${size}" "icon")
                 endforeach()
                 foreach(file ${icons_at_${double_size}px})
-                    copy_icon("${file}" "${size}x${size}@2x")
+                    copy_icon("${file}" "${size}x${size}@2x" "icon")
                 endforeach()
             endforeach()
 
+            # List of supported sizes and filenames taken from:
+            # https://developer.apple.com/library/content/documentation/General/Conceptual/ExtensibilityPG/Finder.html#//apple_ref/doc/uid/TP40014214-CH15-SW15
+            foreach(file ${sidebar_icons_at_16px})
+                copy_icon("${file}" "16x16" "sidebar")
+            endforeach()
+            foreach(file ${sidebar_icons_at_32px})
+                copy_icon("${file}" "16x16@2x" "sidebar")
+            endforeach()
+            foreach(file ${sidebar_icons_at_32px})
+                copy_icon("${file}" "18x18" "sidebar")
+            endforeach()
+            foreach(file ${sidebar_icons_at_64px})
+                copy_icon("${file}" "18x18@2x" "sidebar")
+            endforeach()
+            foreach(file ${sidebar_icons_at_128px})
+                copy_icon("${file}" "32x32" "sidebar")
+            endforeach()
+            foreach(file ${sidebar_icons_at_256px})
+                copy_icon("${file}" "32x32@2x" "sidebar")
+            endforeach()
+
             # generate .icns icon file
             add_custom_command(
                 OUTPUT "${_outfilename}.icns"
@@ -257,20 +342,58 @@ function(ecm_add_app_icon appsources)
                     --convert icns
                     --output "${_outfilename}.icns"
                     "${_outfilename}.iconset"
-                DEPENDS ${iconset_icons}
+                DEPENDS "${iconset_icons}"
                 WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}"
             )
             # This will register the icon into the bundle
-            set(MACOSX_BUNDLE_ICON_FILE ${appsources}.icns PARENT_SCOPE)
+            set(MACOSX_BUNDLE_ICON_FILE "${_outfilebasename}.icns" PARENT_SCOPE)
 
             # Append the icns file to the sources list so it will be a dependency to the
             # main target
             set(${appsources} "${${appsources}};${_outfilename}.icns" PARENT_SCOPE)
 
             # Install the icon into the Resources dir in the bundle
-            set_source_files_properties(${_outfilename}.icns PROPERTIES MACOSX_PACKAGE_LOCATION Resources)
+            set_source_files_properties("${_outfilename}.icns" PROPERTIES MACOSX_PACKAGE_LOCATION Resources)
         else()
             message(STATUS "Unable to find the iconutil utility - application will not have an application icon!")
         endif()
     endif()
 endfunction()
+
+macro(_ecm_add_app_icon_categorize_icons icons type known_sizes)
+    set(_${type}_known_sizes)
+    foreach(size ${known_sizes})
+        set(${type}_at_${size}px)
+        list(APPEND _${type}_known_sizes ${size})
+    endforeach()
+
+
+    foreach(icon ${icons})
+        get_filename_component(icon_full ${icon} ABSOLUTE)
+        if (NOT EXISTS "${icon_full}")
+            message(AUTHOR_WARNING "${icon_full} does not exist, ignoring")
+        else()
+            get_filename_component(icon_name ${icon} NAME)
+            string(REGEX MATCH "([0-9]+)\\-[^/]+\\.([a-z]+)$"
+                               _dummy "${icon_name}")
+            set(size  "${CMAKE_MATCH_1}")
+            set(ext   "${CMAKE_MATCH_2}")
+
+            if (NOT (ext STREQUAL "svg" OR ext STREQUAL "svgz"))
+                if (NOT size)
+                    message(AUTHOR_WARNING "${icon_full} is not named correctly for ecm_add_app_icon - ignoring")
+                elseif (NOT ext STREQUAL "png")
+                    message(AUTHOR_WARNING "${icon_full} is not a png file - ignoring")
+                else()
+                    list(FIND _${type}_known_sizes ${size} offset)
+
+                    if (offset GREATER -1)
+                        list(APPEND ${type}_at_${size}px "${icon_full}")
+                    elseif()
+                        message(STATUS "not found ${type}_at_${size}px ${icon_full}")
+                    endif()
+                endif()
+            endif()
+        endif()
+    endforeach()
+endmacro()
diff --git a/tests/ECMAddAppIconTest/128-category-name-sidebar.png b/tests/ECMAddAppIconTest/128-category-name-sidebar.png
new file mode 100644
index 00000000..fa32c2a5
--- /dev/null
+++ b/tests/ECMAddAppIconTest/128-category-name-sidebar.png
diff --git a/tests/ECMAddAppIconTest/16-category-name-sidebar.png b/tests/ECMAddAppIconTest/16-category-name-sidebar.png
new file mode 100644
index 00000000..4d7b7ddb
--- /dev/null
+++ b/tests/ECMAddAppIconTest/16-category-name-sidebar.png
diff --git a/tests/ECMAddAppIconTest/CMakeLists.txt b/tests/ECMAddAppIconTest/CMakeLists.txt
index dc556c1d..93dfd562 100644
--- a/tests/ECMAddAppIconTest/CMakeLists.txt
+++ b/tests/ECMAddAppIconTest/CMakeLists.txt
@@ -8,18 +8,57 @@ set(CMAKE_MODULE_PATH
 
 include(ECMAddAppIcon)
 
-set(ICONS 16-category-name.png 128-category-name.png)
+if(WIN32)
+    set(icon_extension_to_test "rc")
+elseif(APPLE)
+    set(icon_extension_to_test "icns")
+endif()
+
+#### Test 1: ecm_add_app_icon with only regular icons and no OUTFILE_BASENAME ####
+set(ICONS_1 16-category-name.png 128-category-name.png)
+ecm_add_app_icon(OUT_1 ICONS ${ICONS_1})
+
+if(WIN32 OR APPLE)
+    list(LENGTH OUT_1 out_count)
+    if(out_count EQUAL 0)
+        message(FATAL_ERROR "ecm_add_app_icon() hasn't produced anything")
+    endif()
+
+
+    if(NOT OUT_1 MATCHES "OUT_1.${icon_extension_to_test}")
+        message(FATAL_ERROR "ecm_add_app_icon() did not fall back to target name for icon name: ${OUT_1}")
+    endif()
+endif()
+
+add_custom_target(t_1 ALL DEPENDS ${OUT_1})
+list(APPEND OUT "${OUT_1}")
+
+#### Test 2: ecm_add_app_icon with regular and sidebar icons and OUTFILE_BASENAME set ####
+set(ICONS_2 16-category-name.png 128-category-name.png)
+set(SIDEBAR_ICONS_2 16-category-name-sidebar.png 128-category-name-sidebar.png)
 
-ecm_add_app_icon(OUT ICONS ${ICONS})
+ecm_add_app_icon(OUT_2 ICONS ${ICONS_2} SIDEBAR_ICONS ${SIDEBAR_ICONS_2} OUTFILE_BASENAME "SuperBasename")
 
 if(WIN32 OR APPLE)
-    list(LENGTH OUT out_count)
+    list(LENGTH OUT_2 out_count)
     if(out_count EQUAL 0)
-        message(FATAL_ERROR "ecm_add_app_icon() haven't produced anything")
+        message(FATAL_ERROR "ecm_add_app_icon() hasn't produced anything")
     endif()
+
+    if(NOT OUT_2 MATCHES "SuperBasename.${icon_extension_to_test}")
+        message(FATAL_ERROR "ecm_add_app_icon() did not respect OUTFILE_BASENAME: ${OUT_2}")
+    endif()
+endif()
+
+if(APPLE)
+    list(APPEND expected_icons "icon_16x16.png" "icon_128x128.png" "sidebar_16x16.png" "sidebar_32x32.png")
+    foreach(expected_icon ${expected_icons})
+        list(APPEND OUT_2 "${CMAKE_CURRENT_BINARY_DIR}/SuperBasename.iconset/${expected_icon}")
+    endforeach()
 endif()
 
-add_custom_target(t ALL DEPENDS ${OUT})
+add_custom_target(t_2 ALL DEPENDS ${OUT_2})
+list(APPEND OUT "${OUT_2}")
 
-# this will be run by CTest
+#### this will be run by CTest ####
 configure_file(check_files.cmake.in "${CMAKE_CURRENT_BINARY_DIR}/check_files.cmake" @ONLY)
diff --git a/tests/ECMAddAppIconTest/check_files.cmake.in b/tests/ECMAddAppIconTest/check_files.cmake.in
index e7beb272..09f98315 100644
--- a/tests/ECMAddAppIconTest/check_files.cmake.in
+++ b/tests/ECMAddAppIconTest/check_files.cmake.in
@@ -6,4 +6,4 @@ foreach(f ${FILES})
         message(SEND_ERROR "${f} was not found")
     endif()
 endforeach()
-endif()
\ No newline at end of file
+endif()