added test coverage in doc
@@ -272,6 +272,10 @@ Code quality
* Code quality: https://landscape.io/github/gammapy/gammapy/master
* Code coverage: https://coveralls.io/r/gammapy/gammapy
+To run all tests and measure coverage, type the command ``make test-cov``::
+
+ $ make test-cov
+
Releases
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