Add trickier test case

apache · May 24, 2019 · c590d0f · c590d0f
1 parent 8bf8ebc
commit c590d0f
Showing 1 changed file with 38 additions and 0 deletions.
diff --git a/tests/python/relay/test_pass_unmatched_cases.py b/tests/python/relay/test_pass_unmatched_cases.py
@@ -146,6 +146,44 @@ def test_multiple_constructor_clauses():
     assert len(unmatched_cases(match, mod)) == 0
 
 
+def test_missing_in_the_middle():
+    mod = relay.Module()
+    p = Prelude(mod)
+
+    v = relay.Var('v')
+    match = relay.Match(v, [
+        # list of length exactly 1
+        relay.Clause(
+            relay.PatternConstructor(p.cons, [relay.PatternWildcard(),
+                                              relay.PatternConstructor(p.nil, [])]), v),
+        # empty list
+        relay.Clause(
+            relay.PatternConstructor(p.nil, []), v),
+        # list of length 3 or more
+        relay.Clause(
+            relay.PatternConstructor(
+                p.cons, [relay.PatternWildcard(),
+                         relay.PatternConstructor(
+                             p.cons,
+                             [relay.PatternWildcard(),
+                              relay.PatternConstructor(
+                                  p.cons,
+                                  [relay.PatternWildcard(),
+                                   relay.PatternWildcard()])])]),
+            v)
+    ])
+
+    # fails to match a list of length exactly two
+    unmatched = unmatched_cases(match, mod)
+    assert len(unmatched) == 1
+    assert isinstance(unmatched[0], relay.PatternConstructor)
+    assert unmatched[0].constructor == p.cons
+    assert isinstance(unmatched[0].patterns[1], relay.PatternConstructor)
+    assert unmatched[0].patterns[1].constructor == p.cons
+    assert isinstance(unmatched[0].patterns[1].patterns[1], relay.PatternConstructor)
+    assert unmatched[0].patterns[1].patterns[1].constructor == p.nil
+
+
 def test_mixed_adt_constructors():
     mod = relay.Module()
     box = relay.GlobalTypeVar('box')