As reported in bug 310674, the Desktop Entry spec says that whitespace surrounding the = sign that separates the key and value in .desktop files should be ignored when interpreting the key and value portions.

That is, all four of these lines should be equivalent:

Type=Application
Type =Application
Type= Application
Type = Application

DesktopFileParser handles this for most key/value entries already (e.g. at src/lib/plugin/desktopfileparser.cpp:266), but there is a specific function to handle reading Type= entries from desktop files which doesn't handle spaces (and even has a TODO asking whether it should).

This patch implements the spec here by using QRegularExpression to match the part of the string after =\s*.

Existing autotests have been modified to include spaces around some of the Type= entries, and the updated autotests now pass.