added test for the require_version option; added test for extract_version function

tests/requirements_txt_fixer_test.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import _pytest
 import pytest
 
 from pre_commit_hooks.requirements_txt_fixer import FAIL
@@ -111,6 +112,39 @@ def test_integration(input_s, expected_retval, output, tmpdir):
     assert output_retval == expected_retval
 
 
+def test_require_version(tmpdir: _pytest._py.path.LocalPath) -> None:
+    # default: don't require version
+    path = tmpdir.join('file.txt')
+    input_s = (
+        b'a==1\n'
+        b'bbbb\n'
+        b'c>=1\n'
+    )
+    path.write_binary(input_s)
+    output_retval = main([str(path)])
+    assert output_retval == PASS
+
+    # require version, and all the versions are specified
+    input_s = (
+        b'a==1\n'
+        b'bbbb~=2.0\n'
+        b'c>=1\n'
+    )
+    path.write_binary(input_s)
+    output_retval = main([str(path), '--require_version'])
+    assert output_retval == PASS
+
+    # require version, and some of the versions are missing
+    input_s = (
+        b'a\n'
+        b'bbbb~=2.0\n'
+        b'c>=1\n'
+    )
+    path.write_binary(input_s)
+    output_retval = main([str(path), '--require_version'])
+    assert output_retval == FAIL
+
+
 def test_requirement_object():
     top_of_file = Requirement()
     top_of_file.comments.append(b'#foo')
@@ -125,6 +159,8 @@ def test_requirement_object():
     requirement_baz = Requirement()
     requirement_baz.value = b'baz>=1.2.3'
 
+    requirement_empty = Requirement()
+
     # This may look redundant, but we need to test both foo.__lt__(bar) and
     # bar.__lt__(foo)
     assert requirement_foo > top_of_file
@@ -133,6 +169,7 @@ def test_requirement_object():
     assert requirement_bar < requirement_foo
 
     # Test the version extraction code
+    assert requirement_empty.extract_version() is None
     assert not requirement_foo.has_version()
     assert not requirement_bar.has_version()
     assert requirement_baz.has_version()