stage: check that deps exist before running the command

Fixes #1101

Signed-off-by: Ruslan Kuprieiev <[email protected]>

tests/test_run.py

@@ -3,7 +3,7 @@ import filecmp
 
 from dvc.main import main
 from dvc.utils import file_md5
-from dvc.stage import Stage, StageFileBadNameError
+from dvc.stage import Stage, StageFileBadNameError, MissingDep
 from dvc.command.run import CmdRun
 from dvc.exceptions import OutputDuplicationError
 
@@ -55,6 +55,17 @@ class TestRunEmpty(TestDvc):
                      cwd=os.curdir)
 
 
+class TestRunMissingDep(TestDvc):
+    def test(self):
+        with self.assertRaises(MissingDep):
+            self.dvc.run(cmd='',
+                         deps=['non-existing-dep'],
+                         outs=[],
+                         outs_no_cache=[],
+                         fname='empty.dvc',
+                         cwd=os.curdir)
+
+
 class TestRunBadStageFilename(TestDvc):
     def test(self):
         with self.assertRaises(StageFileBadNameError):