edebug-test-coverage is a variable defined in `edebug.el'.
Its value is

If non-nil, Edebug tests coverage of all expressions debugged.
This is done by comparing the result of each expression with the
previous result. Coverage is considered OK if two different
results are found.

Use `edebug-display-freq-count' to display the frequency count and
coverage information for a definition.

You can customize this variable.