feat: let action fail if coverage decreases by threshold

README.md

@@ -23,11 +23,12 @@ Just add this action to one of your [workflow files](https://docs.github.com/en/
 
 The possible inputs for this action are:
 
-| Parameter                           | Description                                                                                                                                                                   | Default                |
-|-------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| ---------------------- |
-| `github-token` (**Required**)       | Github token used for posting the comment. To use the key provided by the GitHub action runner, use `${{ secrets.GITHUB_TOKEN }}`.                                            |                        |
-| `monorepo-base-path` (**Required**) | The location of your monrepo `packages` path                                                                                                                                  |                        |
-| `s3-config`          | Configuration for uploading lcov files to s3. Json Encoded. e.g. '{ credentials: { accessKeyId: "", secretAccessKey: "" }, region: "", Bucket: "repository-code-coverage" }'  |                        |
+| Parameter                           | Description                                                                                                                                                                  | Default |
+|-------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------|
+| `github-token` (**Required**)       | Github token used for posting the comment. To use the key provided by the GitHub action runner, use `${{ secrets.GITHUB_TOKEN }}`.                                           |         |
+| `monorepo-base-path` (**Required**) | The location of your monrepo `packages` path                                                                                                                                 |         |
+| `s3-config`                         | Configuration for uploading lcov files to s3. Json Encoded. e.g. '{ credentials: { accessKeyId: "", secretAccessKey: "" }, region: "", Bucket: "repository-code-coverage" }' |         |
+| `threshold`                         | Sets the threshold before the action fails if coverage of a package decreases                                                                                                | 0.1%    |
 
 ## Examples
 

action.yml

@@ -14,6 +14,9 @@ inputs:
     s3-config:
         description: 's3 config for lcov file storage, json encoded { credentials: { accessKeyId: "", secretAccessKey: "", }, region: "", Bucket: "repository-code-coverage" }'
         required: false
+    threshold:
+        description: 'minimum threshold (in %) before the action fails, default is 0.1%'
+        required: false
 runs:
     using: node16
     main: dist/index.js

src/app.ts

@@ -243,6 +243,7 @@ export async function generateReport(
     prNumber: number,
     base: string,
     mainBase = "master",
+    threshold = 0.1,
 ) {
     const [{ lcovArrayForMonorepo }, { lcovBaseArrayForMonorepo }] =
         await Promise.all([
@@ -266,19 +267,25 @@ export async function generateReport(
         // head: context.payload.pull_request?.head.ref,
         base,
         folder: monorepoBasePath,
+        threshold,
     };
 
+    const diff = generateDiffForMonorepo(
+        lcovArrayForMonorepo,
+        lcovBaseArrayForMonorepo,
+        options,
+    );
+
     await upsertComment(
         client,
         repo,
         prNumber,
-        generateDiffForMonorepo(
-            lcovArrayForMonorepo,
-            lcovBaseArrayForMonorepo,
-            options,
-        ),
+        diff.text,
         `<!-- monorepo-code-coverage-assistant--${monorepoBasePath} -->`,
     );
 
-    return lcovArrayForMonorepo.length;
+    return {
+        count: lcovArrayForMonorepo.length,
+        thresholdReached: diff.thresholdReached,
+    };
 }

src/cli.ts

@@ -77,6 +77,7 @@ try {
         const options = {
             base: "base...",
             folder: monorepoBasePath.split("/")[1],
+            threshold: 0.1,
         };
 
         // eslint-disable-next-line no-console

src/comment.ts

@@ -20,9 +20,10 @@ const renderEmoji = (pdiff: number) => {
 export const generateDiffForMonorepo = (
     lcovArrayForMonorepo: LvocList,
     lcovBaseArrayForMonorepo: LvocList,
-    options: { base: string; folder: string },
-): string => {
+    options: { base: string; folder: string; threshold: number },
+): { text: string; thresholdReached: number } => {
     const { base, folder } = options;
+    let thresholdReached = 0;
     const rows = lcovArrayForMonorepo.map((lcovObj) => {
         const baseLcov = lcovBaseArrayForMonorepo.find(
             (el) => el.packageName === lcovObj.packageName,
@@ -31,6 +32,10 @@ export const generateDiffForMonorepo = (
         const pbefore = baseLcov ? percentage(baseLcov.lcov) : 0;
         const pafter = baseLcov ? percentage(lcovObj.lcov) : 0;
         const pdiff = pafter - pbefore;
+
+        if (pdiff < -options.threshold) {
+            thresholdReached += 1;
+        }
         const plus = pdiff > 0 ? "+" : "";
 
         let arrow = "";
@@ -64,7 +69,14 @@ export const generateDiffForMonorepo = (
 
     const title = `Coverage for the ${b(folder)} folder after merging into ${b(
         base,
-    )} <p></p>`;
+    )} ${
+        thresholdReached
+            ? `warning: ${b(`decresased for ${thresholdReached} packages`)}`
+            : ":"
+    } <p></p>`;
 
-    return fragment(title, html);
+    return {
+        text: fragment(title, html),
+        thresholdReached,
+    };
 };

src/html.ts

@@ -1,5 +1,5 @@
 const tag =
-    (name: string) =>
+    (name: string, inline = false) =>
     (...children: any[]) => {
         const props =
             typeof children[0] === "object"
@@ -11,16 +11,16 @@ const tag =
         const c =
             typeof children[0] === "string" ? children : children.slice(1);
 
-        return `<${name}${props}>${c.join("")}</${name}>\n`;
+        return `<${name}${props}>${c.join("")}</${name}>${!inline ? "\n" : ""}`;
     };
 
 export const tr = tag("tr");
 export const td = tag("td");
 export const th = tag("th");
-export const b = tag("b");
+export const b = tag("b", true);
 export const table = tag("table");
 export const tbody = tag("tbody");
-export const a = tag("a");
+export const a = tag("a", true);
 export const span = tag("span");
 
 export const fragment = (...children: string[]) => children.join("");

src/index.ts

@@ -10,6 +10,7 @@ import {
 const token = getInput("github-token");
 const monorepoBasePath = getInput("monorepo-base-path");
 const s3Config = getInput("s3-config");
+const threshold = getInput("threshold");
 const base = context.payload.pull_request?.base.ref;
 
 try {
@@ -59,18 +60,22 @@ try {
 
         const client = getOctokit(token);
 
-        const cntReport = await generateReport(
+        const resultReport = await generateReport(
             client,
             s3Client,
             s3ConfigParsed?.Bucket,
             monorepoBasePath,
             context.repo,
             context.payload.pull_request.number,
             base,
+            undefined,
+            (threshold && parseInt(threshold, 10)) || undefined,
         );
 
         // eslint-disable-next-line no-console
-        console.info(`generated report for ${cntReport} lcov files`);
+        console.info(
+            `generated report for ${resultReport.count} lcov files, ${resultReport.thresholdReached}x thresholds reached`,
+        );
 
         if (s3Client && s3ConfigParsed) {
             const cntUpload = await uploadTemporaryLvocFiles(
@@ -85,6 +90,12 @@ try {
             // eslint-disable-next-line no-console
             console.info(`uploaded ${cntUpload} temporary lcov files`);
         }
+
+        if (resultReport.thresholdReached) {
+            setFailed(
+                `coverage decreased over threshold for ${resultReport.thresholdReached} packages`,
+            );
+        }
     }
 } catch (err) {
     console.error(err);

test/html.test.ts

@@ -4,10 +4,10 @@ test("html tags should return the correct html", () => {
     expect(tr("foo", "bar")).toBe("<tr>foobar</tr>\n");
     expect(td("foo", "bar")).toBe("<td>foobar</td>\n");
     expect(th("foo", "bar")).toBe("<th>foobar</th>\n");
-    expect(b("foo", "bar")).toBe("<b>foobar</b>\n");
+    expect(b("foo", "bar")).toBe("<b>foobar</b>");
     expect(table("foo", "bar")).toBe("<table>foobar</table>\n");
     expect(tbody("foo", "bar")).toBe("<tbody>foobar</tbody>\n");
-    expect(a("foo", "bar")).toBe("<a>foobar</a>\n");
+    expect(a("foo", "bar")).toBe("<a>foobar</a>");
     expect(span("foo", "bar")).toBe("<span>foobar</span>\n");
 });
 
@@ -19,9 +19,9 @@ test("html fragment should return the children", () => {
 
 test("html tags should accept props", () => {
     expect(a({ href: "http://www.example.com" }, "example")).toBe(
-        "<a href='http://www.example.com'>example</a>\n",
+        "<a href='http://www.example.com'>example</a>",
     );
     expect(
         a({ href: "http://www.example.com", target: "_blank" }, "example"),
-    ).toBe("<a href='http://www.example.com' target='_blank'>example</a>\n");
+    ).toBe("<a href='http://www.example.com' target='_blank'>example</a>");
 });