Add test for double substitution using {{ }}

{{foo}} uses the result of {foo} as the name for substitution.

1 files changed, 14 insertions, 0 deletions

diff --git a/tests/test_config.py b/tests/test_config.py
index 6176641..a027e91 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -1006,6 +1006,20 @@ class TestConfigTestEnv:
         argv = conf.commands
         assert argv[0] == ["echo"]
 
+    def test_substitution_double(self, newconfig):
+        inisource = """
+            [params]
+            foo = bah
+            foo2 = [params]foo
+            
+            [testenv:py27]
+            commands =
+                echo {{[params]foo2}}
+        """
+        conf = newconfig([], inisource).envconfigs['py27']
+        argv = conf.commands
+        assert argv[0] == ['echo', 'bah']
+
     def test_posargs_backslashed_or_quoted(self, tmpdir, newconfig):
         inisource = """
             [testenv:py27]