test.py: compute coverage per top-level module.

infra/.coveragerc

Index: infra/.coveragerc
diff --git a/.coveragerc b/infra/.coveragerc
similarity index 50%
rename from .coveragerc
rename to infra/.coveragerc
index b5c4220678516ddc93633b5fa16de5296b3336b2..d655349b62a08e0d40782bd8b02a0b8c65cf5e85 100644
--- a/.coveragerc
+++ b/infra/.coveragerc
@@ -1,22 +1,6 @@
 [run]
-include = ./*
+include = ./infra/*
 omit =
-    # Virtual environment with third_party packages.
-    ./ENV/*
-
-    # Add chromium_build, which wasn't test.py-enabled for a long time.
-    ./appengine/chromium_build/*
-
-    # Add monorail's third-party packages and worst offenders
-    ./appengine/monorail/third_party/*
-    ./appengine/monorail/testing/*
-
-    # Appengine third_party packages, committed into the repo as is.
-    ./appengine/third_party/*
-
-    # Luci code added via DEPS.
-    ./luci/*
-
     # Antibody third_party files
     ./infra/tools/antibody/static/third_party/*
 
@@ -38,4 +22,4 @@ exclude_lines =
     if __name__ == ['"]__main__['"]:
 
 [expect_tests]
-expected_coverage_min = 92
+expected_coverage_min = 100