fix(edit): collapsed unchanged diff context between distant edit blocks

- Updated generateDiffString to preserve bounded context at both edges of unchanged regions between adjacent changes by adding a middle skip and ellipsis. - Added a test covering distant edit hunks to verify unchanged lines in the gap are collapsed while change lines remain visible.
2026-04-26 03:17:55 +02:00
parent 985f2049ab
commit c82df1367d
2 changed files with 61 additions and 22 deletions
@@ -0,0 +1,22 @@
+import { describe, expect, it } from "bun:test";
+import { generateDiffString } from "../../src/edit/diff";
+
+describe("generateDiffString", () => {
+	it("collapses unchanged lines between distant edits", () => {
+		const oldLines = Array.from({ length: 20 }, (_, index) => `line ${index + 1}`);
+		const newLines = [...oldLines];
+		newLines[1] = "line 2 changed";
+		newLines[17] = "line 18 changed";
+
+		const result = generateDiffString(oldLines.join("\n"), newLines.join("\n"), 2);
+		const diffLines = result.diff.split("\n");
+
+		expect(diffLines).toContain(" 5|...");
+		expect(diffLines).toContain("-2|line 2");
+		expect(diffLines).toContain("+2|line 2 changed");
+		expect(diffLines).toContain("-18|line 18");
+		expect(diffLines).toContain("+18|line 18 changed");
+		expect(diffLines).not.toContain(" 8|line 8");
+		expect(diffLines).not.toContain(" 12|line 12");
+	});
+});