Add tests for the seq module (#87)

Author: chrisrink10

basilisp/lang/seq.py

@@ -100,7 +100,7 @@ def rest(self) -> Optional["Seq[T]"]:
             n = next(self._seq)
             return _Sequence(self._seq, n)
         except StopIteration:
-            return None
+            return _EmptySequence()
 
     def cons(self, elem):
         return Cons(elem, self)
@@ -132,3 +132,7 @@ def sequence(s: Iterable) -> Seq[Any]:
         return _Sequence(i, next(i))
     except StopIteration:
         return _EmptySequence()
+
+
+def empty() -> Seq[Any]:
+    return _EmptySequence()

tests/seq_test.py

@@ -0,0 +1,27 @@
+import basilisp.lang.list as llist
+import basilisp.lang.seq as lseq
+
+
+def test_to_sequence():
+    assert lseq.empty() == lseq.sequence([])
+    assert llist.l(1) == lseq.sequence([1])
+    assert llist.l(1, 2, 3) == lseq.sequence([1, 2, 3])
+
+
+def test_empty_sequence():
+    empty = lseq.sequence([])
+    assert None is empty.first
+    assert empty.rest == empty
+    assert llist.l(1) == empty.cons(1)
+    assert lseq.empty() == empty
+
+
+def test_sequence():
+    s = lseq.sequence([1])
+    assert 1 == s.first
+    assert lseq.empty() == s.rest
+    assert llist.l(2, 1) == s.cons(2)
+    assert [1, 2, 3] == [e for e in lseq.sequence([1, 2, 3])]
+    assert llist.l(1, 2, 3) == lseq.sequence([1, 2, 3])
+    assert llist.l(1, 2, 3) == lseq.sequence(llist.l(1, 2, 3))
+    assert llist.l(1, 2, 3) == llist.list(lseq.sequence([1, 2, 3]))