Allow len(Version) to return number of split components. (#7918)

lib/spack/spack/test/versions.py

@@ -488,6 +488,14 @@ def check_repr_and_str(vrs):
     check_repr_and_str('R2016a.2-3_4')
 
 
+def test_len():
+    a = Version('1.2.3.4')
+    assert len(a) == len(a.version)
+    assert(len(a) == 4)
+    b = Version('2018.0')
+    assert(len(b) == 2)
+
+
 def test_get_item():
     a = Version('0.1_2-3')
     assert isinstance(a[1], int)

lib/spack/spack/version.py

@@ -253,6 +253,9 @@ def satisfies(self, other):
     def __iter__(self):
         return iter(self.version)
 
+    def __len__(self):
+        return len(self.version)
+
     def __getitem__(self, idx):
         cls = type(self)