Unittests and stream apply

.gitignore

@@ -1 +1,2 @@
 dist/
+__pycache__/

src/morgslib/morgslib.py

@@ -24,14 +24,16 @@ Tn = TypeVar('Tn')
 class Stream(Generic[T]):
 
     iter: Iterator[T]
+    singleton: bool = False
 
-    def __init__(self, base: Iterable[T]|Iterator[T]) -> None:
+    def __init__(self, base: Iterable[T]|Iterator[T]|T) -> None:
         if isinstance(base, Iterator):
             self.iter = base
         elif isinstance(base, Iterable):
             self.iter = iter(base)
         else:
-            raise TypeError("Stream base must be an Iterable or Iterator!")  # pyright: ignore[reportUnreachable]
+            self.iter = iter((base, ))
+            singleton = True
     
     def __iter__(self) -> Self:
         return self
@@ -48,14 +50,22 @@ class Stream(Generic[T]):
     def first(self, fxn: Callable[[T], bool]) -> T | None:
         return next(filter(fxn, self.iter), None)
 
-    def groupby(self, fxn: Callable[[T], Tn]) -> Stream[tuple[Tn, list[T]]]:
+    def group(self, fxn: Callable[[T], Tn]) -> Stream[tuple[Tn, list[T]]]:
         out: defaultdict[Tn, list[T]] = defaultdict(list)
         for item in self.iter:
             out[fxn(item)].append(item)
         return Stream(out.items())
 
+    def apply(self, fxn: Callable[[Iterator[T]], Iterable[Tn]|Tn]) -> Stream[Tn]:
+        return Stream(fxn(self.iter))
+    
+    def apply_single(self, fxn: Callable[[T], Iterable[Tn]|Tn]) -> Stream[Tn]:
+        return Stream(fxn(next(self.iter)))
+
     def to(self, fxn: Callable) -> Any:
         return fxn(self.iter)
+    def to_single(self, fxn: Callable) -> Any:
+        return fxn(next(self.iter))
 
     def print(self, sep=","):
         print(*self.iter, sep=sep)

src/morgslib/msl_tests.py

@@ -0,0 +1,32 @@
+import unittest
+
+from morgslib import Stream
+
+class TestStringMethods(unittest.TestCase):
+
+    def test_stream_iterable(self):
+        self.assertIsInstance(Stream([1, 2, 3]), Stream)
+    def test_stream_iterator(self):
+        self.assertIsInstance(Stream(iter([1, 2, 3])), Stream)
+    def test_stream_singleton(self):
+        self.assertIsInstance(Stream(17), Stream)
+
+    def test_map(self):
+        self.assertEqual(Stream([1, 2, 3, 4, 5]).map(lambda x: x*x).to(list), [1, 4, 9, 16, 25])
+    def test_filter(self):
+        self.assertEqual(Stream([1, 2, 3, 4, 5]).filter(lambda x: x%2 == 0).to(list), [2, 4])
+    
+    def test_first(self):
+        self.assertEqual(Stream([1, 2, 3, 4, 5]).first(lambda x: x>3), 4)
+    def test_group(self):
+        self.assertEqual(Stream([1, 2, 3, 4, 5]).group(lambda x: x%3).to(dict), {0: [3], 1: [1, 4], 2: [2, 5]})
+
+    def test_apply_single(self):
+        self.assertEqual(Stream([1, 2, 3, 4, 5]).apply(sum).to_single(int), 15)
+    def test_apply_multi(self):
+        self.assertEqual(Stream(["a", "b", "c"]).apply("".join).to(list), ["a", "b", "c"])
+    def test_singleton_methods(self):
+        self.assertEqual(Stream(5).apply_single(range).to(list), [0, 1, 2, 3, 4])
+
+if __name__ == '__main__':
+    unittest.main()