Merge branch 'liw/warn-if-empty-input'

4 files changed, 20 insertions, 4 deletions

diff --git a/yarn b/yarn
index d9b2b47..fdf81a0 100755
--- a/yarn
+++ b/yarn
@@ -68,7 +68,9 @@ class YarnRunner(cliapp.Application):
     def parse_scenarios(self, filenames):
         mdparser = yarnlib.MarkdownParser()
         for filename in filenames:
-            mdparser.parse_file(filename)
+            blocks = mdparser.parse_file(filename)
+            if not blocks:
+                logging.warning('No scenario code blocks in %s' % filename)
 
         block_parser = yarnlib.BlockParser()
         block_parser.parse_blocks(mdparser.blocks)
diff --git a/yarn.tests/warn-if-empty.script b/yarn.tests/warn-if-empty.script
new file mode 100755
index 0000000..7a5c028
--- /dev/null
+++ b/yarn.tests/warn-if-empty.script
@@ -0,0 +1,10 @@
+#!/bin/sh
+
+set -eu
+
+touch "$DATADIR/empty.yarn"
+
+# The grep below will fail unless the string exists, thereby failing the
+# entire test.
+./yarn --log=/dev/stdout "$DATADIR/empty.yarn" |
+    grep 'No scenario code blocks' > /dev/null
diff --git a/yarnlib/mdparser.py b/yarnlib/mdparser.py
index 9917f8b..7884630 100644
--- a/yarnlib/mdparser.py
+++ b/yarnlib/mdparser.py
@@ -68,6 +68,7 @@ class MarkdownParser(object):
         f = StringIO.StringIO()
         markdown.markdown(text, output=f, extensions=[ext])
         self.blocks.extend(ext.blocks)
+        return ext.blocks
 
     def parse_file(self, filename): # pragma: no cover
         with open(filename) as f:
diff --git a/yarnlib/mdparser_tests.py b/yarnlib/mdparser_tests.py
index a9b9cb7..099ff2b 100644
--- a/yarnlib/mdparser_tests.py
+++ b/yarnlib/mdparser_tests.py
@@ -27,7 +27,7 @@ class MarkdownParserTests(unittest.TestCase):
         self.parser = yarnlib.MarkdownParser()
 
     def test_finds_code_block(self):
-        self.parser.parse_string('''
+        result = self.parser.parse_string('''
 This is blah blah text.
 
     this is a code block
@@ -35,6 +35,7 @@ This is blah blah text.
 More text.
 ''')
         self.assertEqual(self.parser.blocks, ['this is a code block\n'])
+        self.assertEqual(result, ['this is a code block\n'])
 
     def test_finds_consecutive_code_blocks_as_one(self):
         self.parser.parse_string('''
@@ -83,11 +84,13 @@ More text.
         self.assertEqual(self.parser.blocks, ['this is a code block\n'])
 
     def test_parses_multiple_files(self):
-        self.parser.parse_string('''
+        result1 = self.parser.parse_string('''
     block 1
 ''')
-        self.parser.parse_string('''
+        result2 = self.parser.parse_string('''
     block 2
 ''')
+        self.assertEqual(result1, ['block 1\n'])
+        self.assertEqual(result2, ['block 2\n'])
         self.assertEqual(self.parser.blocks, ['block 1\n', 'block 2\n'])