test: add command line test for multi-search-replace (#2220)

Adds a new test case that allows testing the multi-search-replace diff strategy directly from the command line by passing source and diff files as arguments.

This enables easier debugging and manual testing of the diff application functionality without needing to modify test code for each test case.

Signed-off-by: Eric Wheeler <[email protected]>
Co-authored-by: Eric Wheeler <[email protected]>

src/core/diff/strategies/__tests__/multi-search-replace.test.ts

@@ -1510,6 +1510,121 @@ function five() {
 					expect(result.success).toBe(false)
 					expect(result.error).toContain("'=======' found in your diff content")
 				})
+
+				describe("command line processing", () => {
+					let strategy: MultiSearchReplaceDiffStrategy
+					beforeEach(() => {
+						strategy = new MultiSearchReplaceDiffStrategy()
+					})
+
+					it("should process diff from command line arguments", async () => {
+						// This test is designed to be run from the command line with file arguments
+						// Example: npx jest src/core/diff/strategies/__tests__/multi-search-replace.test.ts -t "should process diff" -- file.ts diff.diff
+
+						// Get command line arguments
+						const args = process.argv.slice(2)
+
+						// Skip test if not run with arguments
+						// Parse command line arguments for --source and --diff flags
+						let sourceFile: string | undefined
+						let diffFile: string | undefined
+
+						for (let i = 0; i < args.length; i++) {
+							if (args[i] === "--source" && i + 1 < args.length) {
+								sourceFile = args[i + 1]
+								i++ // Skip the next argument as it's the value
+							} else if (args[i] === "--diff" && i + 1 < args.length) {
+								diffFile = args[i + 1]
+								i++ // Skip the next argument as it's the value
+							}
+						}
+
+						if (!sourceFile || !diffFile) {
+							console.debug(
+								`Optional debug usage: npx jest multi-search-replace.test.ts -- --source <file.ts> --diff <diff.diff>\n`,
+							)
+							// console.debug('All args:', args);
+							return
+						}
+
+						try {
+							// Read files
+							const fs = require("fs")
+							const sourceContent = fs.readFileSync(sourceFile, "utf8")
+							let diffContent = fs.readFileSync(diffFile, "utf8")
+
+							// Show first 50 lines of source content
+							process.stdout.write(
+								`\n\n====================================================================\n`,
+							)
+							process.stdout.write(`== ${sourceFile} first 50 lines ==\n`)
+							process.stdout.write(
+								`====================================================================\n`,
+							)
+							sourceContent
+								.split("\n")
+								.slice(0, 50)
+								.forEach((line: string) => {
+									process.stdout.write(`${line}\n`)
+								})
+							process.stdout.write(
+								`=============================== END ================================\n`,
+							)
+
+							process.stdout.write(
+								`\n\n====================================================================\n`,
+							)
+							process.stdout.write(`== ${diffFile} first 50 lines ==\n`)
+							process.stdout.write(
+								`====================================================================\n`,
+							)
+
+							// Show first 50 lines of diff content
+							diffContent
+								.split("\n")
+								.slice(0, 50)
+								.forEach((line: string) => {
+									process.stdout.write(`${line}\n`)
+								})
+							process.stdout.write(
+								`=============================== END ================================\n`,
+							)
+
+							// Apply the diff
+							const result = await strategy.applyDiff(sourceContent, diffContent)
+
+							if (result.success) {
+								process.stdout.write(
+									`\n\n====================================================================\n`,
+								)
+								process.stdout.write(`== Diff applied successfully ==\n`)
+								process.stdout.write(
+									`====================================================================\n`,
+								)
+								process.stdout.write(result.content + "\n")
+								process.stdout.write(
+									`=============================== END ================================\n`,
+								)
+								expect(result.success).toBe(true)
+							} else {
+								process.stdout.write(
+									`\n\n====================================================================\n`,
+								)
+								process.stdout.write(`== Failed to apply diff ==\n`)
+								process.stdout.write(
+									`====================================================================\n\n\n`,
+								)
+								console.error(result)
+								process.stdout.write(
+									`=============================== END ================================\n\n\n`,
+								)
+							}
+						} catch (err) {
+							console.error("Error processing files:", err.message)
+							console.error("Stack trace:", err.stack)
+						}
+					})
+				})
 			})
 
 			it("should not strip content that starts with pipe but no line number", async () => {