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

infra_libs/.coveragerc

Index: infra_libs/.coveragerc
diff --git a/infra_libs/.coveragerc b/infra_libs/.coveragerc
new file mode 100644
index 0000000000000000000000000000000000000000..b041e2e6dbbecc8e7a083148ee03aae44d3d01b1
--- /dev/null
+++ b/infra_libs/.coveragerc
@@ -0,0 +1,22 @@
+[run]
+include = ./infra_libs/*
+
+[report]
+exclude_lines =
+    # Have to re-enable the standard pragma
+    pragma: no cover
+
+    # Don't complain about missing debug-only code:
+    def __repr__
+    if self\.debug
+
+    # Don't complain if tests don't hit defensive assertion code:
+    raise AssertionError
+    raise NotImplementedError
+
+    # Don't complain if non-runnable code isn't run:
+    if 0:
+    if __name__ == ['"]__main__['"]:
+
+[expect_tests]
+expected_coverage_min = 100