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Testing GrepHandler Pattern Matching and Line Control Features in Arthas

This test suite validates the GrepHandler functionality in Alibaba’s Arthas core, focusing on various grep command options and pattern matching capabilities. The tests verify text processing with different line control parameters, pattern matching modes, and output formatting options.

Test Coverage Overview

The test suite provides comprehensive coverage of GrepHandler functionality:

Line control testing with -A (after), -B (before), and -C (context) options
Pattern inversion testing with -v option
Regular expression pattern matching with -e option
Maximum match count limiting with -m option
Line number display with -n option

Implementation Analysis

The testing approach uses parameterized test cases with sample input-output pairs to validate different grep options. Each test method focuses on specific grep functionality using JUnit’s testing framework. The implementation employs a structured array-based test data organization for multiple scenarios verification.

Technical Details

Testing Framework: JUnit 4
Test Style: Parameterized testing
Key Classes: GrepHandler
Test Data Structure: Object arrays for input/expected pairs
Assertion Methods: assertEquals for string comparison

Best Practices Demonstrated

The test suite demonstrates several testing best practices:

Systematic test case organization with clear naming conventions
Comprehensive edge case coverage
Parameterized test data for multiple scenarios
Isolated test methods for specific functionality
Clear input-output validation patterns

alibaba/arthas

core/src/test/java/com/taobao/arthas/core/shell/command/internal/GrepHandlerTest.java

            
package com.taobao.arthas.core.shell.command.internal;

import org.junit.Assert;
import org.junit.Test;

public class GrepHandlerTest {

    @Test
    public void test4grep_ABC() { // -A -B -C
        Object[][] samples = new Object[][] { { "ABC\n1\n2\n3\n4\nc", "ABC", 0, 4, "ABC\n1\n2\n3\n4" },
                        { "ABC\n1\n2\n3\n4\nABC\n5", "ABC", 2, 1, "ABC\n1\n3\n4\nABC\n5" },
                        { "ABC\n1\n2\n3\n4\na", "ABC", 2, 1, "ABC\n1" }, { "ABC\n1\n2\n3\n4\nb", "ABC", 0, 0, "ABC" },
                        { "ABC\n1\n2\n3\n4\nc", "ABC", 0, 5, "ABC\n1\n2\n3\n4\nc" },
                        { "ABC\n1\n2\n3\n4\nc", "ABC", 0, 10, "ABC\n1\n2\n3\n4\nc" },
                        { "ABC\n1\n2\n3\n4\nc", "ABC", 0, 2, "ABC\n1\n2" },
                        { "1\n2\n3\n4\nABC", "ABC", 5, 1, "1\n2\n3\n4\nABC" },
                        { "1\n2\n3\n4\nABC", "ABC", 4, 1, "1\n2\n3\n4\nABC" },
                        { "1\n2\n3\n4\nABC", "ABC", 2, 1, "3\n4\nABC" } };

        for (Object[] args : samples) {
            String word = (String) args[1];
            int beforeLines = (Integer) args[2];
            int afterLines = (Integer) args[3];
            GrepHandler handler = new GrepHandler(word, false, false, true, false, true, beforeLines, afterLines, 0);
            String input = (String) args[0];
            final String ret = handler.apply(input);
            final String expected = (String) args[4];
            Assert.assertEquals(expected, ret.substring(0, ret.length() - 1));
        }
    }

    @Test
    public void test4grep_v() {// -v
        Object[][] samples = new Object[][] { { "ABC\n1\n2\nc", "ABC", 0, 4, "1\n2\nc" },
                        { "ABC\n1\n2\n", "ABC", 0, 0, "1\n2" }, { "ABC\n1\n2\nc", "ABC", 0, 1, "1\n2\nc" } };

        for (Object[] args : samples) {
            String word = (String) args[1];
            int beforeLines = (Integer) args[2];
            int afterLines = (Integer) args[3];
            GrepHandler handler = new GrepHandler(word, false, true, true, false, true, beforeLines, afterLines, 0);
            String input = (String) args[0];
            final String ret = handler.apply(input);
            final String expected = (String) args[4];
            Assert.assertEquals(expected, ret.substring(0, ret.length() - 1));
        }
    }

    @Test
    public void test4grep_e() {// -e
        Object[][] samples = new Object[][] { { "java\n1python\n2\nc", "java|python", "java\n1python" },
                        { "java\n1python\n2\nc", "ja|py", "java\n1python" } };

        for (Object[] args : samples) {
            String word = (String) args[1];
            GrepHandler handler = new GrepHandler(word, false, false, true, false, true, 0, 0, 0);
            String input = (String) args[0];
            final String ret = handler.apply(input);
            final String expected = (String) args[2];
            Assert.assertEquals(expected, ret.substring(0, ret.length() - 1));
        }
    }

    @Test
    public void test4grep_m() {// -e
        Object[][] samples = new Object[][] { { "java\n1python\n2\nc", "java|python", "java", 1 },
                        { "java\n1python\n2\nc", "ja|py", "java\n1python", 2 },
                        { "java\n1python\n2\nc", "ja|py", "java\n1python", 3 } };

        for (Object[] args : samples) {
            String word = (String) args[1];
            int maxCount = args.length > 3 ? (Integer) args[3] : 0;
            GrepHandler handler = new GrepHandler(word, false, false, true, false, true, 0, 0, maxCount);
            String input = (String) args[0];
            final String ret = handler.apply(input);
            final String expected = (String) args[2];
            Assert.assertEquals(expected, ret.substring(0, ret.length() - 1));
        }
    }

    @Test
    public void test4grep_n() {// -n
        Object[][] samples = new Object[][] { { "java\n1\npython\n2\nc", "1:java\n3:python", "java|python" },
                        { "java\n1\npython\njava\nc", "1:java\n4:java", "java", false } };

        for (Object[] args : samples) {
            String word = (String) args[2];
            boolean regexpMode = args.length > 3 ? (Boolean) args[3] : true;
            GrepHandler handler = new GrepHandler(word, false, false, regexpMode, true, true, 0, 0, 0);
            String input = (String) args[0];
            final String ret = handler.apply(input);
            final String expected = (String) args[1];
            Assert.assertEquals(expected, ret.substring(0, ret.length() - 1));
        }
    }

}