Issue: Cannot supply multiple files to pact-verifier

 - PR: Added deprecation warning instead of making api-breaking change

pact/test/test_verify.py

@@ -149,6 +149,25 @@ def test_all_options(self):
         self.mock_Popen.return_value.communicate.assert_called_once_with(
             timeout=60)
 
+    def test_deprecated_pact_urls(self):
+        self.mock_Popen.return_value.returncode = 0
+        result = self.runner.invoke(verify.main, [
+            '--provider-base-url=http://localhost',
+            '--pact-urls=./pacts/consumer-provider.json',
+            '--pact-urls=./pacts/consumer-provider2.json'
+        ])
+        self.assertEqual(result.exit_code, 0)
+        self.assertIn(
+            b'Multiple --pact-urls arguments are deprecated.',
+            result.output_bytes)
+        self.assertEqual(self.mock_Popen.call_count, 1)
+        self.assertProcess(
+            '--provider-base-url=http://localhost',
+            '--pact-urls=./pacts/consumer-provider.json,'
+            './pacts/consumer-provider2.json')
+        self.mock_Popen.return_value.communicate.assert_called_once_with(
+            timeout=30)
+
 
 class path_existsTestCase(TestCase):
     def setUp(self):

pact/verify.py

@@ -28,7 +28,8 @@
     default='',
     help='The URI(s) of the pact to verify.'
          ' Can be an HTTP URI(s) or local file path(s).'
-         ' Provide multiple URI separated by a comma.')
+         ' Provide multiple URI separated by a comma.',
+    multiple=True)  # Remove in major version 1.0.0
 @click.option(
     'states_url', '--provider-states-url',
     help='URL to fetch the provider states for the given provider API.')
@@ -59,6 +60,7 @@ def main(base_url, pact_url, pact_urls, states_url, states_setup_url, username,
         pact-verifier --provider-base-url=http://localhost:8080 --pact-url=./pact
     """  # NOQA
     error = click.style('Error:', fg='red')
+    warning = click.style('Warning:', fg='yellow')
     if bool(states_url) != bool(states_setup_url):
         click.echo(
             error
@@ -67,7 +69,16 @@ def main(base_url, pact_url, pact_urls, states_url, states_setup_url, username,
         raise click.Abort()
 
     all_pact_urls = list(pact_url)
-    all_pact_urls.extend(p for p in pact_urls.split(',') if p)
+    for urls in pact_urls:  # Remove in major version 1.0.0
+        all_pact_urls.extend(p for p in urls.split(',') if p)
+
+    if len(pact_urls) > 1:
+        click.echo(
+            warning
+            + ' Multiple --pact-urls arguments are deprecated. '
+              'Please provide a comma separated list of pacts to --pact-urls, '
+              'or multiple --pact-url arguments.')
+
     if not all_pact_urls:
         click.echo(
             error