Add a coveragerc (#4180)

.coveragerc

+[run]
+branch = True
+parallel = True
+source = synapse
+
+[paths]
+source=
+   coverage
+
+[report]
+precision = 2
+ignore_errors = True

MANIFEST.in

@@ -34,6 +34,7 @@ prune .github
 prune demo/etc
 prune docker
 prune .circleci
+prune .coveragerc
 
 exclude jenkins*
 recursive-exclude jenkins *.sh

changelog.d/4180.misc

+A coveragerc file, as well as the py36-coverage tox target, have been added.

tox.ini

@@ -70,7 +70,7 @@ usedevelop=true
 usedevelop=true
 deps =
     {[base]deps}
-     psycopg2
+    psycopg2
 setenv =
     {[base]setenv}
     SYNAPSE_POSTGRES = 1
@@ -101,11 +101,22 @@ usedevelop=true
 [testenv:py36]
 usedevelop=true
 
+
+[testenv:py36-coverage]
+usedevelop=true
+deps =
+    {[base]deps}
+    coverage
+commands =
+    /usr/bin/find "{toxinidir}" -name '*.pyc' -delete
+    python -m coverage run -m twisted.trial {env:TRIAL_FLAGS:} {posargs:tests} {env:TOXSUFFIX:}
+
+
 [testenv:py36-postgres]
 usedevelop=true
 deps =
     {[base]deps}
-     psycopg2
+    psycopg2
 setenv =
     {[base]setenv}
     SYNAPSE_POSTGRES = 1