add [PUB] popularity badge (#7920)

* add PUB popularity badge

* update PUB popularity badge

* update PUB popularity badge

Co-authored-by: repo-ranger[bot] <39074581+repo-ranger[bot]@users.noreply.github.com>

services/pub/pub-popularity.service.js

+import Joi from 'joi'
+import { floorCount } from '../color-formatters.js'
+import { BaseJsonService } from '../index.js'
+
+const documentation = `<p>A measure of how many developers use a package, providing insight into what other developers are using.</p>`
+
+const keywords = ['dart', 'flutter']
+
+const schema = Joi.object({
+  popularityScore: Joi.number().min(0).max(1).required(),
+}).required()
+
+const title = 'Pub Popularity'
+
+export default class PubPopularity extends BaseJsonService {
+  static category = 'rating'
+
+  static route = { base: 'pub/popularity', pattern: ':packageName' }
+
+  static examples = [
+    {
+      title,
+      keywords,
+      documentation,
+      namedParams: { packageName: 'analysis_options' },
+      staticPreview: this.render({ popularityScore: 0.9 }),
+    },
+  ]
+
+  static defaultBadgeData = { label: 'popularity' }
+
+  static render({ popularityScore }) {
+    const roundedScore = Math.round(popularityScore * 100)
+    return {
+      label: 'popularity',
+      message: `${roundedScore}%`,
+      color: floorCount(roundedScore, 40, 60, 80),
+    }
+  }
+
+  async fetch({ packageName }) {
+    return this._requestJson({
+      schema,
+      url: `https://pub.dev/api/packages/${packageName}/score`,
+    })
+  }
+
+  async handle({ packageName }) {
+    const score = await this.fetch({ packageName })
+    const popularityScore = score.popularityScore
+    return this.constructor.render({ popularityScore })
+  }
+}

services/pub/pub-popularity.tester.js

+import { isIntegerPercentage } from '../test-validators.js'
+import { createServiceTester } from '../tester.js'
+
+export const t = await createServiceTester()
+
+t.create('pub popularity (valid)').get('/analysis_options.json').expectBadge({
+  label: 'popularity',
+  message: isIntegerPercentage,
+})
+
+t.create('pub popularity (not found)')
+  .get('/analysisoptions.json')
+  .expectBadge({
+    label: 'popularity',
+    message: 'not found',
+    color: 'red',
+  })
+
+t.create('pub popularity (invalid)').get('/analysis-options.json').expectBadge({
+  label: 'popularity',
+  message: 'invalid',
+  color: 'lightgrey',
+})