Add an StrSubject for basename to FileSubject

CHANGELOG.md

@@ -8,7 +8,7 @@
 
 * `TargetSubject.provider()` and `TargetSubject.has_provider()` accept a
   `provider_name` for better error messaging.
-
+* Added `FileSubject.basename()` and `FileSubject.actual`
 ### Added
 
 * Nothing yet

lib/private/file_subject.bzl

@@ -32,6 +32,8 @@ def _file_subject_new(file, meta):
     # buildifier: disable=uninitialized
     public = struct(
         # keep sorted start
+        actual = file,
+        basename = lambda *a, **k: _file_subject_basename(self, *a, **k),
         equals = lambda *a, **k: _file_subject_equals(self, *a, **k),
         path = lambda *a, **k: _file_subject_path(self, *a, **k),
         short_path_equals = lambda *a, **k: _file_subject_short_path_equals(self, *a, **k),
@@ -40,6 +42,19 @@ def _file_subject_new(file, meta):
     self = struct(file = file, meta = meta, public = public)
     return public
 
+def _file_subject_basename(self):
+    """Returns a `StrSubject` asserting on the files `basename` value.
+
+    Method: FileSubject.basename
+
+    Returns:
+        [`StrSubject`] object.
+    """
+    return StrSubject.new(
+        self.file.basename,
+        meta = self.meta.derive("basename()"),
+    )
+
 def _file_subject_equals(self, expected):
     """Asserts that `expected` references the same file as `self`.
 
@@ -100,5 +115,6 @@ FileSubject = struct(
     new = _file_subject_new,
     equals = _file_subject_equals,
     path = _file_subject_path,
+    basename = _file_subject_basename,
     short_path_equals = _file_subject_short_path_equals,
 )

tests/truth_tests.bzl

@@ -1206,6 +1206,7 @@ def _file_subject_test(env, target):
     expect = truth.expect(fake_env)
     subject = expect.that_file(target.files.to_list()[0])
     subject.short_path_equals(package + "/testdata/file1.txt")
+    subject.basename().equals("file1.txt")
     _assert_no_failures(fake_env, env = env)
 
     subject.short_path_equals("landon-and-hope-forever.txt")