feat: Add file coverage compare logic

src/report/generateFileCoverageHtml.test.ts

@@ -11,6 +11,7 @@ import {
 	createMockReportNumbers,
 } from "../types/JsonSummaryMockFactory";
 import { generateFileCoverageHtml } from "./generateFileCoverageHtml";
+import { icons } from "../icons";
 
 const workspacePath = process.cwd();
 describe("generateFileCoverageHtml()", () => {
@@ -30,9 +31,11 @@ describe("generateFileCoverageHtml()", () => {
 
 		const html = generateFileCoverageHtml({
 			jsonSummary,
+			jsonSummaryCompare: undefined,
 			jsonFinal: {},
 			fileCoverageMode: FileCoverageMode.All,
 			pullChanges: [],
+			commitSHA: "test-sha",
 		});
 
 		const firstTableLine = getTableLine(1, html);
@@ -50,9 +53,11 @@ describe("generateFileCoverageHtml()", () => {
 
 		const html = generateFileCoverageHtml({
 			jsonSummary,
+			jsonSummaryCompare: undefined,
 			jsonFinal: {},
 			fileCoverageMode: FileCoverageMode.All,
 			pullChanges: [relativeChangedFilePath],
+			commitSHA: "test-sha",
 		});
 
 		expect(getTableLine(1, html)).toContain("Changed Files");
@@ -69,9 +74,11 @@ describe("generateFileCoverageHtml()", () => {
 
 		const html = generateFileCoverageHtml({
 			jsonSummary,
+			jsonSummaryCompare: undefined,
 			jsonFinal: {},
 			fileCoverageMode: FileCoverageMode.All,
 			pullChanges: [changedFileName],
+			commitSHA: "test-sha",
 		});
 
 		expect(html).not.toContain("Unchanged Files");
@@ -84,9 +91,11 @@ describe("generateFileCoverageHtml()", () => {
 
 		const html = generateFileCoverageHtml({
 			jsonSummary,
+			jsonSummaryCompare: undefined,
 			jsonFinal: {},
 			fileCoverageMode: FileCoverageMode.Changes,
 			pullChanges: [],
+			commitSHA: "test-sha",
 		});
 
 		expect(html).toContain("No changed files found.");
@@ -104,9 +113,11 @@ describe("generateFileCoverageHtml()", () => {
 
 		const html = generateFileCoverageHtml({
 			jsonSummary,
+			jsonSummaryCompare: undefined,
 			jsonFinal: {},
 			fileCoverageMode: FileCoverageMode.All,
 			pullChanges: [],
+			commitSHA: "test-sha",
 		});
 
 		const tableLine = getTableLine(2, html);
@@ -132,9 +143,11 @@ describe("generateFileCoverageHtml()", () => {
 
 		const html = generateFileCoverageHtml({
 			jsonSummary,
+			jsonSummaryCompare: undefined,
 			jsonFinal,
 			fileCoverageMode: FileCoverageMode.All,
 			pullChanges: [],
+			commitSHA: "test-sha",
 		});
 
 		const tableLine = getTableLine(2, html);
@@ -159,8 +172,10 @@ describe("generateFileCoverageHtml()", () => {
 		const html = generateFileCoverageHtml({
 			jsonSummary,
 			jsonFinal,
+			jsonSummaryCompare: undefined,
 			fileCoverageMode: FileCoverageMode.All,
 			pullChanges: [],
+			commitSHA: "test-sha",
 		});
 
 		const tableLine = getTableLine(2, html);
@@ -187,14 +202,46 @@ describe("generateFileCoverageHtml()", () => {
 
 		const html = generateFileCoverageHtml({
 			jsonSummary,
+			jsonSummaryCompare: undefined,
 			jsonFinal,
 			fileCoverageMode: FileCoverageMode.All,
 			pullChanges: [],
+			commitSHA: "test-sha",
 		});
 
 		const tableLine = getTableLine(2, html);
 
 		expect(tableLine).toContain("#L2");
 		expect(tableLine).toContain("#L5-L6");
 	});
+
+	it("renders an equal sign for files without changes to covergage", () => {
+		const jsonSummary: JsonSummary = createMockJsonSummary({
+			"file1.ts": createMockCoverageReport(),
+		});
+
+		const jsonSummaryCompare: JsonSummary = createMockJsonSummary({
+			"file1.ts": createMockCoverageReport(),
+		});
+		const jsonFinal: JsonFinal = {
+			...createJsonFinalEntry("src/exampleFile.ts", [
+				{ line: 1, covered: true },
+			]),
+		};
+
+		const html = generateFileCoverageHtml({
+			jsonSummary,
+			jsonSummaryCompare,
+			jsonFinal,
+			fileCoverageMode: FileCoverageMode.All,
+			pullChanges: [],
+			commitSHA: "test-sha",
+		});
+
+		expect(html).toContain("file1.ts");
+		expect(html).toContain(icons.equal);
+		const equalSignCount = (html.match(new RegExp(icons.equal, "g")) || [])
+			.length;
+		expect(equalSignCount).toBe(4);
+	});
 });

src/report/generateFileCoverageHtml.ts

@@ -2,15 +2,17 @@ import * as path from "node:path";
 import { oneLine } from "common-tags";
 import { FileCoverageMode } from "../inputs/FileCoverageMode";
 import type { JsonFinal } from "../types/JsonFinal";
-import type { JsonSummary } from "../types/JsonSummary";
+import type { CoverageReport, JsonSummary } from "../types/JsonSummary";
 import { generateBlobFileUrl } from "./generateFileUrl";
 import {
 	type LineRange,
 	getUncoveredLinesFromStatements,
 } from "./getUncoveredLinesFromStatements";
+import { icons } from "../icons";
 
 type FileCoverageInputs = {
 	jsonSummary: JsonSummary;
+	jsonSummaryCompare: JsonSummary | undefined;
 	jsonFinal: JsonFinal;
 	fileCoverageMode: FileCoverageMode;
 	pullChanges: string[];
@@ -20,6 +22,7 @@ type FileCoverageInputs = {
 const workspacePath = process.cwd();
 const generateFileCoverageHtml = ({
 	jsonSummary,
+	jsonSummaryCompare,
 	jsonFinal,
 	fileCoverageMode,
 	pullChanges,
@@ -29,6 +32,9 @@ const generateFileCoverageHtml = ({
 
 	const formatFileLine = (filePath: string) => {
 		const coverageSummary = jsonSummary[filePath];
+		const coverageSummaryCompare = jsonSummaryCompare
+			? jsonSummaryCompare[filePath]
+			: undefined;
 		const lineCoverage = jsonFinal[filePath];
 
 		// LineCoverage might be empty if coverage-final.json was not provided.
@@ -41,10 +47,10 @@ const generateFileCoverageHtml = ({
 		return `
       <tr>
         <td align="left"><a href="${url}">${relativeFilePath}</a></td>
-        <td align="right">${coverageSummary.statements.pct}%</td>
-        <td align="right">${coverageSummary.branches.pct}%</td>
-        <td align="right">${coverageSummary.functions.pct}%</td>
-        <td align="right">${coverageSummary.lines.pct}%</td>
+				<td align="right">${generateCoverageCell(coverageSummary, coverageSummaryCompare, "statements")}</td>
+				<td align="right">${generateCoverageCell(coverageSummary, coverageSummaryCompare, "branches")}</td>
+				<td align="right">${generateCoverageCell(coverageSummary, coverageSummaryCompare, "functions")}</td>
+				<td align="right">${generateCoverageCell(coverageSummary, coverageSummaryCompare, "lines")}</td>
         <td align="left">${createRangeURLs(uncoveredLines, url)}</td>
       </tr>`;
 	};
@@ -96,6 +102,15 @@ const generateFileCoverageHtml = ({
   `;
 };
 
+function generateCoverageCell(
+	summary: CoverageReport,
+	summaryCompare: CoverageReport | undefined,
+	field: keyof CoverageReport,
+): string {
+	const icon = summaryCompare ? icons.equal : "";
+	return `<td align="right">${summary[field].pct}%<br/>${icon}</td>`;
+}
+
 function formatGroupLine(caption: string): string {
 	return `
 		<tr>