CPack: Add test coverage for CPACK_APPIMAGE_VERSION

Verify that the `X-AppImage-Version` entry that appimagetool writes to
the desktop file defaults to `CPACK_PACKAGE_VERSION` and that it can be
overridden with `CPACK_APPIMAGE_VERSION`.

Tests/RunCMake/CPack_AppImage/AppImageTestApp-cpack-AppImage-check.cmake

@@ -1,3 +1,3 @@
-if(NOT EXISTS "${RunCMake_TEST_BINARY_DIR}/GeneratorTest-1.2.3-Linux.AppImage")
-  set(RunCMake_TEST_FAILED "AppImage package not generated")
-endif()
+# CPACK_APPIMAGE_VERSION defaults to CPACK_PACKAGE_VERSION.
+set(expected_version "1.2.3")
+include("${CMAKE_CURRENT_LIST_DIR}/AppImageVersionCheck.cmake")

Tests/RunCMake/CPack_AppImage/AppImageVersion-cpack-AppImage-check.cmake

@@ -0,0 +1,3 @@
+# CPACK_APPIMAGE_VERSION given explicitly overrides CPACK_PACKAGE_VERSION.
+set(expected_version "4.5.6-test")
+include("${CMAKE_CURRENT_LIST_DIR}/AppImageVersionCheck.cmake")

Tests/RunCMake/CPack_AppImage/AppImageVersion-cpack-AppImage-stderr.txt

@@ -0,0 +1,19 @@
+appimagetool[^
+]*
+Using architecture x86_64
+Deleting pre-existing \.DirIcon
+Creating \.DirIcon symlink based on information from desktop file
+WARNING: AppStream upstream metadata is missing, please consider creating it
+         in usr/share/metainfo/com\.example\.app\.appdata\.xml
+         Please see https://www\.freedesktop\.org/software/appstream/docs/chap-Quickstart\.html#sect-Quickstart-DesktopApps
+         for more information or use the generator at
+         https://docs\.appimage\.org/packaging-guide/optional/appstream\.html#using-the-appstream-generator
+Generating squashfs\.\.\.
+Embedding ELF\.\.\.
+Marking the AppImage as executable\.\.\.
+Embedding MD5 digest
+Success
+
+Please consider submitting your AppImage to AppImageHub, the crowd-sourced
+central directory of available AppImages, by opening a pull request
+at https://github\.com/AppImage/appimage\.github\.io

Tests/RunCMake/CPack_AppImage/AppImageVersion-cpack-AppImage-stdout.txt

@@ -0,0 +1,44 @@
+CPack: Create package using AppImage
+CPack: Install projects
+CPack: - Install project: CPackAppImageGenerator \[Release\]
+CPack: Create package
+CPack: AppDir: "[^"]*/_CPack_Packages/Linux/AppImage/GeneratorTest-1\.2\.3-Linux"
+CPack: Found Desktop file: "[^"]*/_CPack_Packages/Linux/AppImage/GeneratorTest-1\.2\.3-Linux/share/applications/com\.example\.app\.desktop"
+CPack: Desktop file destination: "[^"]*/_CPack_Packages/Linux/AppImage/GeneratorTest-1\.2\.3-Linux/com\.example\.app\.desktop"
+CPack: Icon file: "[^"]*/_CPack_Packages/Linux/AppImage/GeneratorTest-1\.2\.3-Linux/share/icons/hicolor/64x64/apps/ApplicationIcon\.png"
+CPack: Icon link destination: "[^"]*/_CPack_Packages/Linux/AppImage/GeneratorTest-1\.2\.3-Linux/ApplicationIcon\.png"
+CPack: No AppRun found, generating a default one that will run: "bin/app"
+CPack: Running AppImageTool: "[^"]*" "[^"]*/_CPack_Packages/Linux/AppImage/GeneratorTest-1\.2\.3-Linux" "\.\./GeneratorTest-1\.2\.3-Linux\.AppImage" "--runtime-file" "[^"]*"
+[^
+]*/_CPack_Packages/Linux/AppImage/GeneratorTest-1\.2\.3-Linux should be packaged as \.\./GeneratorTest-1\.2\.3-Linux\.AppImage
+Parallel mksquashfs: Using [0-9]+ processors
+Creating 4\.0 filesystem on [^
+]*/GeneratorTest-1\.2\.3-Linux\.AppImage, block size [0-9]+\.
+.*
+Exportable Squashfs 4\.0 filesystem, zstd compressed, data block size [0-9]+
+[	]compressed data, compressed metadata, compressed fragments,
+[	]compressed xattrs, compressed ids
+[	]duplicates are removed
+Filesystem size [0-9\.]+ Kbytes \([0-9\.]+ Mbytes\)
+[	][0-9\.]+% of uncompressed filesystem size \([0-9\.]+ Kbytes\)
+Inode table size [0-9]+ bytes \([0-9\.]+ Kbytes\)
+[	][0-9\.]+% of uncompressed inode table size \([0-9]+ bytes\)
+Directory table size [0-9]+ bytes \([0-9\.]+ Kbytes\)
+[	][0-9\.]+% of uncompressed directory table size \([0-9]+ bytes\)
+Number of duplicate files found [0-9]+
+Number of inodes [0-9]+
+Number of files [0-9]+
+Number of fragments [0-9]+
+Number of symbolic links [0-9]+
+Number of device nodes [0-9]+
+Number of fifo nodes [0-9]+
+Number of socket nodes [0-9]+
+Number of directories [0-9]+
+Number of hard-links [0-9]+
+Number of ids \(unique uids \+ gids\) [0-9]+
+Number of uids [0-9]+
+[	]root \([0-9]+\)
+Number of gids [0-9]+
+[	]root \([0-9]+\)
+CPack: - package: [^
+]*/Tests/RunCMake/CPack_AppImage/AppImageVersion-build/GeneratorTest-1\.2\.3-Linux\.AppImage generated\.

Tests/RunCMake/CPack_AppImage/AppImageVersionCheck.cmake

@@ -0,0 +1,28 @@
+# Shared by the *-check.cmake scripts: verify that appimagetool recorded
+# ${expected_version} as X-AppImage-Version in the package's desktop file.
+set(appimage "${RunCMake_TEST_BINARY_DIR}/GeneratorTest-1.2.3-Linux.AppImage")
+if(NOT EXISTS "${appimage}")
+  set(RunCMake_TEST_FAILED "AppImage package not generated")
+  return()
+endif()
+
+set(extract_dir "${RunCMake_TEST_BINARY_DIR}/extract")
+file(REMOVE_RECURSE "${extract_dir}")
+file(MAKE_DIRECTORY "${extract_dir}")
+execute_process(
+  COMMAND "${appimage}" --appimage-extract com.example.app.desktop
+  WORKING_DIRECTORY "${extract_dir}"
+  RESULT_VARIABLE extract_result
+  OUTPUT_QUIET
+  ERROR_VARIABLE extract_error
+  )
+set(desktop_file "${extract_dir}/squashfs-root/com.example.app.desktop")
+if(NOT extract_result EQUAL 0 OR NOT EXISTS "${desktop_file}")
+  set(RunCMake_TEST_FAILED "Failed to extract desktop file from AppImage: ${extract_result}\n${extract_error}")
+  return()
+endif()
+
+file(STRINGS "${desktop_file}" actual_version REGEX "^X-AppImage-Version=")
+if(NOT actual_version STREQUAL "X-AppImage-Version=${expected_version}")
+  set(RunCMake_TEST_FAILED "Expected 'X-AppImage-Version=${expected_version}' in desktop file, got: '${actual_version}'")
+endif()

Tests/RunCMake/CPack_AppImage/RunCMakeTest.cmake

@@ -13,3 +13,8 @@ block()
   list(APPEND RunCMake_TEST_OPTIONS -DCUSTOM_APPRUN=ON)
   run_cpack(AppImageCustomAppRun SAMPLE AppImageUsrPrefix BUILD)
 endblock()
+
+block()
+  list(APPEND RunCMake_TEST_OPTIONS "-DCPACK_APPIMAGE_VERSION=4.5.6-test")
+  run_cpack(AppImageVersion SAMPLE AppImageTestApp BUILD)
+endblock()