diff --git a/.github/workflows/test-package.yml b/.github/workflows/test-package.yml
index 816038e1..cf170eb7 100644
--- a/.github/workflows/test-package.yml
+++ b/.github/workflows/test-package.yml
@@ -54,9 +54,11 @@ jobs:
         python -m pip install --upgrade pip
         pip install -r requirements-dev.txt
     - name: Test install with pytest (including doctests)
+      env:
+        PYTHONWARNINGS: error
       run: |
         python -c "import tests"  # Compiles hissp.basic on package import.
-        pytest -v --cov=hissp --cov-report=xml --doctest-modules --doctest-glob *.md src/hissp/*.lissp tests/ docs/ $(python -c "import hissp; print(hissp.__path__[0])")
+        pytest -p no:cacheprovider -v --cov=hissp --cov-report=xml --doctest-modules --doctest-glob *.md src/hissp/*.lissp tests/ docs/ $(python -c "import hissp; print(hissp.__path__[0])")
     - name: Codecov
       uses: codecov/codecov-action@v1.0.4
       with:
diff --git a/src/hissp/reader.py b/src/hissp/reader.py
index cdc438fb..17d99ae4 100644
--- a/src/hissp/reader.py
+++ b/src/hissp/reader.py
@@ -140,7 +140,7 @@ def __init__(self, token):
         self.token = token
 
     def contents(self):
-        return re.sub(r"\n$|(?m)^ *;+ ?", "", self.token)
+        return re.sub(r"(?m)\n$|^ *;+ ?", "", self.token)
 
     def __repr__(self):
         return f"Comment({self.token!r})"
diff --git a/src/hissp/repl.py b/src/hissp/repl.py
index be651add..bf222b9d 100644
--- a/src/hissp/repl.py
+++ b/src/hissp/repl.py
@@ -88,29 +88,22 @@ def interact(locals=None):
 
 def force_main():
     """:meta private:"""
+    # Creates a new ``__main__`` to take the place of the current
+    # ``__main__`` module.
     __main__ = ModuleType("__main__")
     sys.modules["__main__"] = __main__
     sys.path.insert(0, "")
     return __main__
 
 
-def main(__main__=None):
+def main(__main__):
     """REPL command-line entry point.
 
-    If ``__main__`` is not provided, it creates a new one to take the
-    place of the current ``__main__`` module.
-
     `hissp.macros._macro_` is imported into the module namespace,
     making the bundled macros immediately available unqualified.
     """
-    if not __main__:
-        __main__ = force_main()
     repl = LisspREPL(locals=__main__.__dict__)
     import hissp.macros  # Here so repl can import before compilation.
 
     repl.locals["_macro_"] = SimpleNamespace(**vars(hissp.macros._macro_))
     repl.interact()
-
-
-if __name__ == "__main__":
-    main()
diff --git a/tests/test_cmd.py b/tests/test_cmd.py
index ef67d839..762810b8 100644
--- a/tests/test_cmd.py
+++ b/tests/test_cmd.py
@@ -53,7 +53,7 @@ def test_i_file_args():
 
 
 def test_repl_read_exception():
-    out, err = cmd("python -m hissp.repl", ".#(operator..truediv 1 0)\n")
+    out, err = cmd("python -m hissp", ".#(operator..truediv 1 0)\n")
     assert ">>> # Compilation failed!\nTraceback (most recent call last):\n  F" in err
     assert "\nZeroDivisionError: division by zero" in err
     assert out.count("#> ") == 2