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`diff-view.test.ts`

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82c3a38ccanty labs	1	import { describe, it, expect } from "bun:test";
	2	import { parseDiff, pairLines } from "../lib/diff";
	3
	4	const SIMPLE_DIFF = `diff --git a/src/foo.ts b/src/foo.ts
	5	index abc..def 100644
	6	--- a/src/foo.ts
	7	+++ b/src/foo.ts
	8	@@ -1,5 +1,5 @@
	9	import { bar } from './bar';
	10	-const x = 1;
	11	+const x = 2;
	12	export default x;
	13	`;
	14
	15	const MULTIFILE_DIFF = `diff --git a/a.ts b/a.ts
	16	index 000..111 100644
	17	--- a/a.ts
	18	+++ b/a.ts
	19	@@ -1,2 +1,3 @@
	20	line1
	21	+line2
	22	line3
	23	diff --git a/b.ts b/b.ts
	24	index 222..333 100644
	25	--- a/b.ts
	26	+++ b/b.ts
	27	@@ -1,2 +1,1 @@
	28	hello
	29	-world
	30	`;
	31
	32	const BINARY_DIFF = `diff --git a/image.png b/image.png
	33	index abc..def 100644
	34	Binary files a/image.png and b/image.png differ
	35	`;
	36
	37	const WS_DIFF = `diff --git a/x.ts b/x.ts
	38	index 000..111 100644
	39	--- a/x.ts
	40	+++ b/x.ts
	41	@@ -1,3 +1,3 @@
	42	ctx
	43	- foo
	44	+ foo
	45	ctx
	46	`;
	47
	48	describe("parseDiff", () => {
	49	it("parses a single-file diff with one del and one add", () => {
	50	const files = parseDiff(SIMPLE_DIFF);
	51	expect(files.length).toBe(1);
	52	expect(files[0].path).toBe("src/foo.ts");
	53	expect(files[0].additions).toBe(1);
	54	expect(files[0].deletions).toBe(1);
	55	expect(files[0].isBinary).toBe(false);
	56	});
	57
	58	it("assigns correct line numbers", () => {
	59	const files = parseDiff(SIMPLE_DIFF);
	60	const lines = files[0].lines;
	61	const hunk = lines.find((l) => l.type === "hunk");
	62	expect(hunk).toBeTruthy();
	63	const ctx1 = lines.find((l) => l.type === "ctx");
	64	expect(ctx1?.oldLine).toBe(1);
	65	expect(ctx1?.newLine).toBe(1);
	66	const del = lines.find((l) => l.type === "del");
	67	expect(del?.oldLine).toBe(2);
	68	expect(del?.newLine).toBeNull();
	69	const add = lines.find((l) => l.type === "add");
	70	expect(add?.oldLine).toBeNull();
	71	expect(add?.newLine).toBe(2);
	72	});
	73
	74	it("parses multiple files", () => {
	75	const files = parseDiff(MULTIFILE_DIFF);
	76	expect(files.length).toBe(2);
	77	expect(files[0].path).toBe("a.ts");
	78	expect(files[1].path).toBe("b.ts");
	79	expect(files[0].additions).toBe(1);
	80	expect(files[0].deletions).toBe(0);
	81	expect(files[1].additions).toBe(0);
	82	expect(files[1].deletions).toBe(1);
	83	});
	84
	85	it("marks binary files", () => {
	86	const files = parseDiff(BINARY_DIFF);
	87	expect(files.length).toBe(1);
	88	expect(files[0].isBinary).toBe(true);
	89	expect(files[0].lines.length).toBe(0);
	90	});
	91
	92	it("detects whitespace-only changes", () => {
	93	const files = parseDiff(WS_DIFF);
	94	const lines = files[0].lines;
	95	const del = lines.find((l) => l.type === "del");
	96	const add = lines.find((l) => l.type === "add");
	97	expect(del?.wsOnly).toBe(true);
	98	expect(add?.wsOnly).toBe(true);
	99	});
	100
	101	it("does NOT mark non-whitespace changes as wsOnly", () => {
	102	const files = parseDiff(SIMPLE_DIFF);
	103	const del = files[0].lines.find((l) => l.type === "del");
	104	const add = files[0].lines.find((l) => l.type === "add");
	105	expect(del?.wsOnly).toBeFalsy();
	106	expect(add?.wsOnly).toBeFalsy();
	107	});
	108
	109	it("returns empty array for empty input", () => {
	110	expect(parseDiff("")).toEqual([]);
	111	});
	112
	113	it("handles CRLF line endings", () => {
	114	const crlf = SIMPLE_DIFF.replace(/\n/g, "\r\n");
	115	const files = parseDiff(crlf);
	116	expect(files.length).toBe(1);
	117	expect(files[0].additions).toBe(1);
	118	});
	119
	120	it("strips the +/-/space prefix from content", () => {
	121	const files = parseDiff(SIMPLE_DIFF);
	122	const add = files[0].lines.find((l) => l.type === "add")!;
	123	const del = files[0].lines.find((l) => l.type === "del")!;
	124	expect(add.content).not.toMatch(/^\+/);
	125	expect(del.content).not.toMatch(/^-/);
	126	expect(add.content).toBe("const x = 2;");
	127	expect(del.content).toBe("const x = 1;");
	128	});
	129	});
	130
	131	describe("pairLines", () => {
	132	it("pairs a del/add block into a single row", () => {
	133	const files = parseDiff(SIMPLE_DIFF);
	134	const rows = pairLines(files[0].lines);
	135	const paired = rows.find((r) => r.left?.type === "del" && r.right?.type === "add");
	136	expect(paired).toBeTruthy();
	137	});
	138
	139	it("passes context lines as both left and right", () => {
	140	const files = parseDiff(SIMPLE_DIFF);
	141	const rows = pairLines(files[0].lines);
	142	const ctx = rows.find((r) => r.left?.type === "ctx");
	143	expect(ctx?.left).toBe(ctx?.right);
	144	});
	145
	146	it("pairs hunk headers as both left and right", () => {
	147	const files = parseDiff(SIMPLE_DIFF);
	148	const rows = pairLines(files[0].lines);
	149	const hunk = rows.find((r) => r.left?.type === "hunk");
	150	expect(hunk?.left).toBe(hunk?.right);
	151	});
	152
	153	it("creates null left for orphan add lines", () => {
	154	const files = parseDiff(MULTIFILE_DIFF);
	155	const rows = pairLines(files[0].lines);
	156	const orphanAdd = rows.find((r) => r.left === null && r.right?.type === "add");
	157	expect(orphanAdd).toBeTruthy();
	158	});
	159
	160	it("creates null right for orphan del lines", () => {
	161	const files = parseDiff(MULTIFILE_DIFF);
	162	const rows = pairLines(files[1].lines);
	163	const orphanDel = rows.find((r) => r.right === null && r.left?.type === "del");
	164	expect(orphanDel).toBeTruthy();
	165	});
	166
	167	it("total row count equals unique line count (not doubled)", () => {
	168	const files = parseDiff(SIMPLE_DIFF);
	169	const rows = pairLines(files[0].lines);
	170	// 1 hunk + 1 ctx + 1 paired del/add + 1 ctx = 4 rows
	171	expect(rows.length).toBe(4);
	172	// source has 5 lines: hunk, ctx, del, add, ctx
	173	expect(files[0].lines.length).toBe(5);
	174	});
	175	});