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Testing Git Patch Extension Functionality in pr-agent

This test suite validates the patch extension functionality in pr-agent, focusing on Git patch processing and PR diff generation. It thoroughly tests the extend_patch function’s ability to modify and extend Git patches with additional context lines.

Test Coverage Overview

The test suite provides comprehensive coverage of patch extension scenarios.

Tests happy path with valid input patches
Validates empty patch handling
Tests zero line extensions
Covers single and multiple hunk scenarios
Verifies dynamic context behavior

Implementation Analysis

The testing approach uses pytest fixtures and class-based organization to systematically verify patch extension logic.

Implements setUp methods to control dynamic context settings
Uses fixture-based test data generation
Employs parameterized testing for line number variations

Technical Details

Key technical components include:

pytest framework for test organization
TokenHandler for managing prompt tokens
Custom File class for test data encapsulation
Configuration management through get_settings()

Best Practices Demonstrated

The test suite exemplifies strong testing practices.

Clear test case isolation and setup
Comprehensive edge case coverage
Consistent assertion patterns
Well-structured test data organization

codium-ai/pr-agent

tests/unittest/test_extend_patch.py

            
import pytest

from pr_agent.algo.git_patch_processing import extend_patch
from pr_agent.algo.pr_processing import pr_generate_extended_diff
from pr_agent.algo.token_handler import TokenHandler
from pr_agent.config_loader import get_settings


class TestExtendPatch:
    def setUp(self):
        get_settings().config.allow_dynamic_context = False

    # Tests that the function works correctly with valid input
    def test_happy_path(self):
        original_file_str = 'line1
line2
line3
line4
line5'
        patch_str = '@@ -2,2 +2,2 @@ init()
-line2
+new_line2
 line3'
        num_lines = 1
        expected_output = '
@@ -1,4 +1,4 @@ init()
 line1
-line2
+new_line2
 line3
 line4'
        actual_output = extend_patch(original_file_str, patch_str,
                                     patch_extra_lines_before=num_lines, patch_extra_lines_after=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
line2
line3
line4
line5'
        patch_str = ''
        num_lines = 1
        expected_output = ''
        assert extend_patch(original_file_str, patch_str,
                            patch_extra_lines_before=num_lines, patch_extra_lines_after=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
line2
line3
line4
line5'
        patch_str = '@@ -2,2 +2,2 @@ init()
-line2
+new_line2
line3'
        num_lines = 0
        assert extend_patch(original_file_str, patch_str,
                            patch_extra_lines_before=num_lines, patch_extra_lines_after=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
line2
line3
line4
line5'
        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
line2
line3
line4
line5'
        patch_str = '@@ -2,3 +2,3 @@ init()
-line2
+new_line2
 line3
 line4'

        for num_lines in [1, 2, 3]: # check that even if we are over the number of lines in the file, the function still works
            expected_output = '
@@ -1,5 +1,5 @@ init()
 line1
-line2
+new_line2
 line3
 line4
 line5'
            actual_output = extend_patch(original_file_str, patch_str,
                                         patch_extra_lines_before=num_lines, patch_extra_lines_after=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
line2
line3
line4
line5
line6'
        patch_str = '@@ -2,3 +2,3 @@ init()
-line2
+new_line2
 line3
 line4
@@ -4,1 +4,1 @@ init2()
-line4
+new_line4'  # noqa: E501
        num_lines = 1
        original_allow_dynamic_context = get_settings().config.allow_dynamic_context

        get_settings().config.allow_dynamic_context = False
        expected_output = '
@@ -1,5 +1,5 @@ init()
 line1
-line2
+new_line2
 line3
 line4
 line5

@@ -3,3 +3,3 @@ init2()
 line3
-line4
+new_line4
 line5' # noqa: E501
        actual_output = extend_patch(original_file_str, patch_str,
                                     patch_extra_lines_before=num_lines, patch_extra_lines_after=num_lines)
        assert actual_output == expected_output

        get_settings().config.allow_dynamic_context = True
        expected_output = '
@@ -1,5 +1,5 @@ init()
 line1
-line2
+new_line2
 line3
 line4
 line5

@@ -3,3 +3,3 @@ init2()
 line3
-line4
+new_line4
 line5' # noqa: E501
        actual_output = extend_patch(original_file_str, patch_str,
                                     patch_extra_lines_before=num_lines, patch_extra_lines_after=num_lines)
        assert actual_output == expected_output
        get_settings().config.allow_dynamic_context = original_allow_dynamic_context


    def test_dynamic_context(self):
        get_settings().config.max_extra_lines_before_dynamic_context = 10
        original_file_str = "def foo():"
        for i in range(9):
            original_file_str += f"
    line({i})"
        patch_str ="@@ -11,1 +11,1 @@ def foo():
-    line(9)
+    new_line(9)"
        num_lines=1

        get_settings().config.allow_dynamic_context = True
        actual_output = extend_patch(original_file_str, patch_str,
                                     patch_extra_lines_before=num_lines, patch_extra_lines_after=num_lines)
        expected_output='
@@ -1,10 +1,10 @@ 
 def foo():
     line(0)
     line(1)
     line(2)
     line(3)
     line(4)
     line(5)
     line(6)
     line(7)
     line(8)
-    line(9)
+    new_line(9)'
        assert actual_output == expected_output

        get_settings().config.allow_dynamic_context = False
        actual_output2 = extend_patch(original_file_str, patch_str,
                                     patch_extra_lines_before=num_lines, patch_extra_lines_after=num_lines)
        expected_output_no_dynamic_context = '
@@ -10,1 +10,1 @@ def foo():
     line(8)
-    line(9)
+    new_line(9)'
        assert actual_output2 == expected_output_no_dynamic_context





class TestExtendedPatchMoreLines:
    def setUp(self):
        get_settings().config.allow_dynamic_context = False

    class File:
        def __init__(self, base_file, patch, filename, ai_file_summary=None):
            self.base_file = base_file
            self.patch = patch
            self.filename = filename
            self.ai_file_summary = ai_file_summary

    @pytest.fixture
    def token_handler(self):
        # Create a TokenHandler instance with dummy data
        th = TokenHandler(system="System prompt", user="User prompt")
        th.prompt_tokens = 100
        return th

    @pytest.fixture
    def pr_languages(self):
        # Create a list of languages with files containing base_file and patch data
        return [
            {
                'files': [
                    self.File(base_file="line000
line00
line0
line1
original content
line2
line3
line4
line5
line6
line7
line8
line9
line10",
                              patch="@@ -5,5 +5,5 @@
-original content
+modified content
 line2
 line3
 line4
 line5",
                              filename="file1"),
                    self.File(base_file="original content
line2
line3
line4
line5
line6
line7
line8
line9
line10",
                              patch="@@ -6,5 +6,5 @@
line6
line7
line8
-line9
+modified line9
line10",
                              filename="file2")
                ]
            }
        ]

    def test_extend_patches_with_extra_lines(self, token_handler, pr_languages):
        patches_extended_no_extra_lines, total_tokens, patches_extended_tokens = pr_generate_extended_diff(
            pr_languages, token_handler, add_line_numbers_to_hunks=False,
            patch_extra_lines_before=0,
            patch_extra_lines_after=0
        )

        # Check that with no extra lines, the patches are the same as the original patches
        p0 = patches_extended_no_extra_lines[0].strip()
        p1 = patches_extended_no_extra_lines[1].strip()
        assert p0 == '## file1
' + pr_languages[0]['files'][0].patch.strip()
        assert p1 == '## file2
' + pr_languages[0]['files'][1].patch.strip()

        patches_extended_with_extra_lines, total_tokens, patches_extended_tokens = pr_generate_extended_diff(
            pr_languages, token_handler, add_line_numbers_to_hunks=False,
            patch_extra_lines_before=2,
            patch_extra_lines_after=1
        )

        p0_extended = patches_extended_with_extra_lines[0].strip()
        assert p0_extended == '## file1

@@ -3,8 +3,8 @@ 
 line0
 line1
-original content
+modified content
 line2
 line3
 line4
 line5
 line6'