fix nameko test command (nameko#750)

nameko/cli/__init__.py

@@ -94,4 +94,12 @@ def test(args):
     eventlet.monkey_patch()  # noqa (code before rest of imports)
 
     import pytest
-    pytest.main(list(args))
+    import sys
+
+    args = list(args)
+    args.extend(
+        ["-W", "ignore:Module already imported:_pytest.warning_types.PytestWarning"]
+    )
+
+    exit_code = pytest.main(args)
+    sys.exit(int(exit_code))

test/cli/test_test.py

@@ -0,0 +1,57 @@
+import subprocess
+from textwrap import dedent
+
+import pytest
+
+
+def test_test_pass(tmpdir, capsys):
+
+    tmpdir.join('__init__.py')
+    testfile = tmpdir.join('test_test_pass.py')
+    testfile.write(dedent("""
+        def test_foo():
+            assert True
+    """))
+
+    proc = subprocess.Popen(
+        ["nameko", "test", testfile.strpath], stdout=subprocess.PIPE
+    )
+    proc.wait()
+    assert proc.returncode == 0
+
+
+def test_test_fail(tmpdir, capsys):
+
+    tmpdir.join('__init__.py')
+    testfile = tmpdir.join('test_test_fail.py')
+    testfile.write(dedent("""
+        def test_foo():
+            assert False
+    """))
+
+    proc = subprocess.Popen(
+        ["nameko", "test", testfile.strpath], stdout=subprocess.PIPE
+    )
+    proc.wait()
+    assert proc.returncode == 1
+
+
+def test_suppress_warning(tmpdir, capsys):  # pragma: no cover
+
+    if tuple(map(int, pytest.__version__.split("."))) < (6, 1):
+        pytest.skip("-W flag ignored on older pytests")
+
+    tmpdir.join('__init__.py')
+    testfile = tmpdir.join('test_test_pass.py')
+    testfile.write(dedent("""
+        def test_foo():
+            assert True
+    """))
+
+    proc = subprocess.Popen(
+        ["nameko", "test", testfile.strpath], stdout=subprocess.PIPE
+    )
+    proc.wait()
+
+    out = "".join(map(bytes.decode, proc.stdout.readlines()))
+    assert "Module already imported so cannot be rewritten: nameko" not in out