Add check_requirements() (#1853)

* Add check_requirements()

* add import

* parameterize filename

* add to detect, test

utils/general.py

@@ -53,6 +53,14 @@ def check_git_status():
             print(s[s.find('Your branch is behind'):s.find('\n\n')] + '\n')
 
 
+def check_requirements(file='requirements.txt'):
+    # Check installed dependencies meet requirements
+    import pkg_resources
+    requirements = pkg_resources.parse_requirements(Path(file).open())
+    requirements = [x.name + ''.join(*x.specs) if len(x.specs) else x.name for x in requirements]
+    pkg_resources.require(requirements)  # DistributionNotFound or VersionConflict exception if requirements not met
+
+
 def check_img_size(img_size, s=32):
     # Verify img_size is a multiple of stride s
     new_size = make_divisible(img_size, int(s))  # ceil gs-multiple