add tests and update README.md

tests/unittest/test_extend_patch.py

@@ -0,0 +1,93 @@
+
+# Generated by CodiumAI
+
+
+from pr_agent.algo.git_patch_processing import extend_patch
+
+"""
+Code Analysis
+
+Objective:
+The objective of the 'extend_patch' function is to extend a given patch to include a specified number of surrounding 
+lines. This function takes in an original file string, a patch string, and the number of lines to extend the patch by, 
+and returns the extended patch string.
+
+Inputs:
+- original_file_str: a string representing the original file
+- patch_str: a string representing the patch to be extended
+- num_lines: an integer representing the number of lines to extend the patch by
+
+Flow:
+1. Split the original file string and patch string into separate lines
+2. Initialize variables to keep track of the current hunk's start and size for both the original file and the patch
+3. Iterate through each line in the patch string
+4. If the line starts with '@@', extract the start and size values for both the original file and the patch, and 
+calculate the extended start and size values
+5. Append the extended hunk header to the extended patch lines list
+6. Append the specified number of lines before the hunk to the extended patch lines list
+7. Append the current line to the extended patch lines list
+8. If the line is not a hunk header, append it to the extended patch lines list
+9. Return the extended patch string
+
+Outputs:
+- extended_patch_str: a string representing the extended patch
+
+Additional aspects:
+- The function uses regular expressions to extract the start and size values from the hunk header
+- The function handles cases where the start value of a hunk is less than the number of lines to extend by by setting 
+the extended start value to 1
+- The function handles cases where the hunk extends beyond the end of the original file by only including lines up to 
+the end of the original file in the extended patch
+"""
+
+
+class TestExtendPatch:
+    # Tests that the function works correctly with valid input
+    def test_happy_path(self):
+        original_file_str = 'line1\nline2\nline3\nline4\nline5'
+        patch_str = '@@ -2,2 +2,2 @@ init()\n-line2\n+new_line2\nline3'
+        num_lines = 1
+        expected_output = '@@ -1,4 +1,4 @@ init()\nline1\n-line2\n+new_line2\nline3\nline4'
+        actual_output = extend_patch(original_file_str, patch_str, num_lines)
+        assert actual_output == expected_output
+
+    # Tests that the function returns an empty string when patch_str is empty
+    def test_empty_patch(self):
+        original_file_str = 'line1\nline2\nline3\nline4\nline5'
+        patch_str = ''
+        num_lines = 1
+        expected_output = ''
+        assert extend_patch(original_file_str, patch_str, num_lines) == expected_output
+
+    # Tests that the function returns the original patch when num_lines is 0
+    def test_zero_num_lines(self):
+        original_file_str = 'line1\nline2\nline3\nline4\nline5'
+        patch_str = '@@ -2,2 +2,2 @@ init()\n-line2\n+new_line2\nline3'
+        num_lines = 0
+        assert extend_patch(original_file_str, patch_str, num_lines) == patch_str
+
+    # Tests that the function returns the original patch when patch_str contains no hunks
+    def test_no_hunks(self):
+        original_file_str = 'line1\nline2\nline3\nline4\nline5'
+        patch_str = 'no hunks here'
+        num_lines = 1
+        expected_output = 'no hunks here'
+        assert extend_patch(original_file_str, patch_str, num_lines) == expected_output
+
+    # Tests that the function extends a patch with a single hunk correctly
+    def test_single_hunk(self):
+        original_file_str = 'line1\nline2\nline3\nline4\nline5'
+        patch_str = '@@ -2,3 +2,3 @@ init()\n-line2\n+new_line2\nline3\nline4'
+        num_lines = 1
+        expected_output = '@@ -1,5 +1,5 @@ init()\nline1\n-line2\n+new_line2\nline3\nline4\nline5'
+        actual_output = extend_patch(original_file_str, patch_str, num_lines)
+        assert actual_output == expected_output
+
+    # Tests the functionality of extending a patch with multiple hunks.
+    def test_multiple_hunks(self):
+        original_file_str = 'line1\nline2\nline3\nline4\nline5\nline6'
+        patch_str = '@@ -2,3 +2,3 @@ init()\n-line2\n+new_line2\nline3\nline4\n@@ -4,1 +4,1 @@ init2()\n-line4\n+new_line4'  # noqa: E501
+        num_lines = 1
+        expected_output = '@@ -1,5 +1,5 @@ init()\nline1\n-line2\n+new_line2\nline3\nline4\nline5\n@@ -3,3 +3,3 @@ init2()\nline3\n-line4\n+new_line4\nline5'  # noqa: E501
+        actual_output = extend_patch(original_file_str, patch_str, num_lines)
+        assert actual_output == expected_output