Add regression test for unused files in FileTree

Unused files are correctly highlighted within the tree, but do not correctly
contribute to the summary statistics calculated for their parent directories.

Signed-off-by: John Pennycook <john.pennycook@intel.com>

Author: Pennycook

tests/files/test_filetree.py

@@ -1,12 +1,14 @@
 # Copyright (C) 2019-2024 Intel Corporation
 # SPDX-License-Identifier: BSD-3-Clause
 
+import io
 import logging
 import os
 import tempfile
 import unittest
 from pathlib import Path
 
+from codebasin import CodeBase, finder, report
 from codebasin.report import FileTree
 
 
@@ -30,6 +32,7 @@ def setUpClass(self):
         self.path = Path(self.tmp.name)
         open(self.path / "file.cpp", mode="w").close()
         open(self.path / "other.cpp", mode="w").close()
+        open(self.path / "unused.cpp", mode="w").close()
         os.symlink(self.path / "file.cpp", self.path / "symlink.cpp")
 
     @classmethod
@@ -97,6 +100,59 @@ def test_print(self):
             [f"{meta} \u2500\u2500 {expected_name} -> {expected_link}"],
         )
 
+    def test_report(self):
+        """Check report output is accurate"""
+        stream = io.StringIO()
+        codebase = CodeBase(self.path)
+        configuration = {
+            "X": [
+                {
+                    "file": str(self.path / "file.cpp"),
+                    "defines": [],
+                    "include_paths": [],
+                    "include_files": [],
+                },
+            ],
+            "Y": [
+                {
+                    "file": str(self.path / "other.cpp"),
+                    "defines": [],
+                    "include_paths": [],
+                    "include_files": [],
+                },
+            ],
+        }
+        with open(self.path / "file.cpp", mode="w") as f:
+            f.write("void foo();")
+        with open(self.path / "other.cpp", mode="w") as f:
+            f.write("void bar();")
+        with open(self.path / "unused.cpp", mode="w") as f:
+            f.write("void baz();")
+        state = finder.find(
+            self.path,
+            codebase,
+            configuration,
+            show_progress=False,
+        )
+        report.files(codebase, state, stream=stream)
+        output = stream.getvalue()
+
+        # Skip any header and focus on the tree at the end.
+        lines = output.strip().split("\n")[-5:]
+
+        # Output should contain one line for the directory + each file.
+        self.assertTrue(len(lines) == 5)
+
+        # Check the root directory values include the unused file.
+        self.assertTrue("[AB | 3 |  66.67 |  33.33]" in lines[0])
+
+        # Check the other lines reflect the other files.
+        # The order here isn't guaranteed, so don't check specific lines.
+        self.assertTrue("[A- | 1 | 100.00 |  50.00]" in output)
+        self.assertTrue("[-- | 1 |   0.00 |   0.00]" in output)
+        self.assertTrue("[-B | 1 | 100.00 |  50.00]" in output)
+        self.assertTrue("[A- | 1 | 100.00 |  50.00]" in output)
+
 
 if __name__ == "__main__":
     unittest.main()