Refactor WeatherKit client to injectable interface

- Add WeatherKitClient interface and DefaultWeatherKitClient class
- WeatherKitDataSource accepts either client or credentials
- Simplify tests by injecting mock client directly
- Update fixture generation script to use new client class

Co-authored-by: Ona <no-reply@ona.com>

packages/aris-data-source-weatherkit/scripts/generate-fixtures.ts

@@ -1,4 +1,4 @@
-import { fetchWeather } from "../src/weatherkit"
+import { DefaultWeatherKitClient } from "../src/weatherkit"
 
 function loadEnv(): Record<string, string> {
 	const content = require("fs").readFileSync(".env", "utf-8")
@@ -26,12 +26,12 @@ function loadEnv(): Record<string, string> {
 
 const env = loadEnv()
 
-const credentials = {
+const client = new DefaultWeatherKitClient({
 	privateKey: env.WEATHERKIT_PRIVATE_KEY!,
 	keyId: env.WEATHERKIT_KEY_ID!,
 	teamId: env.WEATHERKIT_TEAM_ID!,
 	serviceId: env.WEATHERKIT_SERVICE_ID!,
-}
+})
 
 const locations = {
 	sanFrancisco: { lat: 37.7749, lng: -122.4194 },
@@ -40,10 +40,10 @@ const locations = {
 async function main() {
 	console.log("Fetching weather data for San Francisco...")
 
-	const response = await fetchWeather(
+	const response = await client.fetch({
-		{ credentials },
+		lat: locations.sanFrancisco.lat,
-		{ lat: locations.sanFrancisco.lat, lng: locations.sanFrancisco.lng },
+		lng: locations.sanFrancisco.lng,
-	)
+	})
 
 	const fixture = {
 		generatedAt: new Date().toISOString(),

packages/aris-data-source-weatherkit/src/data-source.test.ts

@@ -1,11 +1,12 @@
 import type { Context } from "@aris/core"
 
-import { describe, expect, mock, test } from "bun:test"
+import { describe, expect, test } from "bun:test"
+
+import type { WeatherKitClient, WeatherKitResponse } from "./weatherkit"
 
 import fixture from "../fixtures/san-francisco.json"
 import { WeatherKitDataSource, Units } from "./data-source"
 import { WeatherFeedItemType } from "./feed-items"
-import * as weatherkit from "./weatherkit"
 
 const mockCredentials = {
 	privateKey: "mock",
@@ -14,6 +15,10 @@ const mockCredentials = {
 	serviceId: "mock",
 }
 
+const createMockClient = (response: WeatherKitResponse): WeatherKitClient => ({
+	fetch: async () => response,
+})
+
 const createMockContext = (location?: { lat: number; lng: number }): Context => ({
 	time: new Date("2026-01-17T00:00:00Z"),
 	location: location ? { ...location, accuracy: 10 } : undefined,
@@ -32,6 +37,12 @@ describe("WeatherKitDataSource", () => {
 
 		expect(dataSource.type).toBe(WeatherFeedItemType.current)
 	})
+
+	test("throws error if neither client nor credentials provided", () => {
+		expect(() => new WeatherKitDataSource({})).toThrow(
+			"Either client or credentials must be provided",
+		)
+	})
 })
 
 describe("WeatherKitDataSource with fixture", () => {
@@ -103,19 +114,11 @@ describe("unit conversion", () => {
 	})
 })
 
-describe("query() with mocked API", () => {
+describe("query() with mocked client", () => {
-	const mockFetchWeather = mock(() =>
+	const mockClient = createMockClient(fixture.response as WeatherKitResponse)
-		Promise.resolve(fixture.response as weatherkit.WeatherKitResponse),
-	)
 
 	test("transforms API response into feed items", async () => {
-		mock.module("./weatherkit", () => ({
+		const dataSource = new WeatherKitDataSource({ client: mockClient })
-			...weatherkit,
-			fetchWeather: mockFetchWeather,
-		}))
-
-		const { WeatherKitDataSource } = await import("./data-source")
-		const dataSource = new WeatherKitDataSource({ credentials: mockCredentials })
 		const context = createMockContext({ lat: 37.7749, lng: -122.4194 })
 
 		const items = await dataSource.query(context)
@@ -127,14 +130,8 @@ describe("query() with mocked API", () => {
 	})
 
 	test("applies hourly and daily limits", async () => {
-		mock.module("./weatherkit", () => ({
-			...weatherkit,
-			fetchWeather: mockFetchWeather,
-		}))
-
-		const { WeatherKitDataSource } = await import("./data-source")
 		const dataSource = new WeatherKitDataSource({
-			credentials: mockCredentials,
+			client: mockClient,
 			hourlyLimit: 3,
 			dailyLimit: 2,
 		})
@@ -150,13 +147,7 @@ describe("query() with mocked API", () => {
 	})
 
 	test("sets timestamp from context.time", async () => {
-		mock.module("./weatherkit", () => ({
+		const dataSource = new WeatherKitDataSource({ client: mockClient })
-			...weatherkit,
-			fetchWeather: mockFetchWeather,
-		}))
-
-		const { WeatherKitDataSource } = await import("./data-source")
-		const dataSource = new WeatherKitDataSource({ credentials: mockCredentials })
 		const queryTime = new Date("2026-01-17T12:00:00Z")
 		const context = createMockContext({ lat: 37.7749, lng: -122.4194 })
 		context.time = queryTime
@@ -169,13 +160,7 @@ describe("query() with mocked API", () => {
 	})
 
 	test("converts temperatures to imperial", async () => {
-		mock.module("./weatherkit", () => ({
+		const dataSource = new WeatherKitDataSource({ client: mockClient })
-			...weatherkit,
-			fetchWeather: mockFetchWeather,
-		}))
-
-		const { WeatherKitDataSource, Units } = await import("./data-source")
-		const dataSource = new WeatherKitDataSource({ credentials: mockCredentials })
 		const context = createMockContext({ lat: 37.7749, lng: -122.4194 })
 
 		const metricItems = await dataSource.query(context, { units: Units.metric })
@@ -187,7 +172,6 @@ describe("query() with mocked API", () => {
 		expect(metricCurrent).toBeDefined()
 		expect(imperialCurrent).toBeDefined()
 
-		// Imperial temp should be higher (F > C for typical weather temps)
 		const metricTemp = (metricCurrent!.data as { temperature: number }).temperature
 		const imperialTemp = (imperialCurrent!.data as { temperature: number }).temperature
 
@@ -197,13 +181,7 @@ describe("query() with mocked API", () => {
 	})
 
 	test("assigns priority based on weather conditions", async () => {
-		mock.module("./weatherkit", () => ({
+		const dataSource = new WeatherKitDataSource({ client: mockClient })
-			...weatherkit,
-			fetchWeather: mockFetchWeather,
-		}))
-
-		const { WeatherKitDataSource } = await import("./data-source")
-		const dataSource = new WeatherKitDataSource({ credentials: mockCredentials })
 		const context = createMockContext({ lat: 37.7749, lng: -122.4194 })
 
 		const items = await dataSource.query(context)
@@ -220,13 +198,7 @@ describe("query() with mocked API", () => {
 	})
 
 	test("generates unique IDs for each item", async () => {
-		mock.module("./weatherkit", () => ({
+		const dataSource = new WeatherKitDataSource({ client: mockClient })
-			...weatherkit,
-			fetchWeather: mockFetchWeather,
-		}))
-
-		const { WeatherKitDataSource } = await import("./data-source")
-		const dataSource = new WeatherKitDataSource({ credentials: mockCredentials })
 		const context = createMockContext({ lat: 37.7749, lng: -122.4194 })
 
 		const items = await dataSource.query(context)

packages/aris-data-source-weatherkit/src/data-source.ts

@@ -10,12 +10,13 @@ import {
 } from "./feed-items"
 import {
 	ConditionCode,
+	DefaultWeatherKitClient,
 	Severity,
-	fetchWeather,
 	type CurrentWeather,
 	type DailyForecast,
 	type HourlyForecast,
 	type WeatherAlert,
+	type WeatherKitClient,
 	type WeatherKitCredentials,
 } from "./weatherkit"
 
@@ -27,7 +28,8 @@ export const Units = {
 export type Units = (typeof Units)[keyof typeof Units]
 
 export interface WeatherKitDataSourceOptions {
-	credentials: WeatherKitCredentials
+	credentials?: WeatherKitCredentials
+	client?: WeatherKitClient
 	hourlyLimit?: number
 	dailyLimit?: number
 }
@@ -41,12 +43,15 @@ export class WeatherKitDataSource implements DataSource<WeatherFeedItem, Weather
 	private readonly DEFAULT_DAILY_LIMIT = 7
 
 	readonly type = WeatherFeedItemType.current
-	private readonly credentials: WeatherKitCredentials
+	private readonly client: WeatherKitClient
 	private readonly hourlyLimit: number
 	private readonly dailyLimit: number
 
 	constructor(options: WeatherKitDataSourceOptions) {
-		this.credentials = options.credentials
+		if (!options.client && !options.credentials) {
+			throw new Error("Either client or credentials must be provided")
+		}
+		this.client = options.client ?? new DefaultWeatherKitClient(options.credentials!)
 		this.hourlyLimit = options.hourlyLimit ?? this.DEFAULT_HOURLY_LIMIT
 		this.dailyLimit = options.dailyLimit ?? this.DEFAULT_DAILY_LIMIT
 	}
@@ -59,13 +64,10 @@ export class WeatherKitDataSource implements DataSource<WeatherFeedItem, Weather
 		const units = config.units ?? Units.metric
 		const timestamp = context.time
 
-		const response = await fetchWeather(
+		const response = await this.client.fetch({
-			{ credentials: this.credentials },
+			lat: context.location.lat,
-			{
+			lng: context.location.lng,
-				lat: context.location.lat,
+		})
-				lng: context.location.lng,
-			},
-		)
 
 		const items: WeatherFeedItem[] = []
 

packages/aris-data-source-weatherkit/src/index.ts

@@ -26,10 +26,13 @@ export {
 	Certainty,
 	PrecipitationType,
 	ConditionCode,
+	DefaultWeatherKitClient,
 	type Severity as SeverityType,
 	type Urgency as UrgencyType,
 	type Certainty as CertaintyType,
 	type PrecipitationType as PrecipitationTypeType,
 	type ConditionCode as ConditionCodeType,
 	type WeatherKitCredentials,
+	type WeatherKitClient,
+	type WeatherKitQueryOptions,
 } from "./weatherkit"

packages/aris-data-source-weatherkit/src/weatherkit.ts

@@ -3,42 +3,6 @@
 
 import { type } from "arktype"
 
-export async function fetchWeather(
-	options: WeatherKitClientOptions,
-	query: WeatherKitQueryOptions,
-): Promise<WeatherKitResponse> {
-	const token = await generateJwt(options.credentials)
-
-	const dataSets = ["currentWeather", "forecastHourly", "forecastDaily", "weatherAlerts"].join(",")
-
-	const url = new URL(
-		`${WEATHERKIT_API_BASE}/weather/${query.language ?? "en"}/${query.lat}/${query.lng}`,
-	)
-	url.searchParams.set("dataSets", dataSets)
-	if (query.timezone) {
-		url.searchParams.set("timezone", query.timezone)
-	}
-
-	const response = await fetch(url.toString(), {
-		headers: {
-			Authorization: `Bearer ${token}`,
-		},
-	})
-
-	if (!response.ok) {
-		throw new Error(`WeatherKit API error: ${response.status} ${response.statusText}`)
-	}
-
-	const json = await response.json()
-	const result = weatherKitResponseSchema(json)
-
-	if (result instanceof type.errors) {
-		throw new Error(`WeatherKit API response validation failed: ${result.summary}`)
-	}
-
-	return result
-}
-
 export interface WeatherKitCredentials {
 	privateKey: string
 	keyId: string
@@ -46,10 +10,6 @@ export interface WeatherKitCredentials {
 	serviceId: string
 }
 
-export interface WeatherKitClientOptions {
-	credentials: WeatherKitCredentials
-}
-
 export interface WeatherKitQueryOptions {
 	lat: number
 	lng: number
@@ -57,6 +17,53 @@ export interface WeatherKitQueryOptions {
 	timezone?: string
 }
 
+export interface WeatherKitClient {
+	fetch(query: WeatherKitQueryOptions): Promise<WeatherKitResponse>
+}
+
+export class DefaultWeatherKitClient implements WeatherKitClient {
+	private readonly credentials: WeatherKitCredentials
+
+	constructor(credentials: WeatherKitCredentials) {
+		this.credentials = credentials
+	}
+
+	async fetch(query: WeatherKitQueryOptions): Promise<WeatherKitResponse> {
+		const token = await generateJwt(this.credentials)
+
+		const dataSets = ["currentWeather", "forecastHourly", "forecastDaily", "weatherAlerts"].join(
+			",",
+		)
+
+		const url = new URL(
+			`${WEATHERKIT_API_BASE}/weather/${query.language ?? "en"}/${query.lat}/${query.lng}`,
+		)
+		url.searchParams.set("dataSets", dataSets)
+		if (query.timezone) {
+			url.searchParams.set("timezone", query.timezone)
+		}
+
+		const response = await fetch(url.toString(), {
+			headers: {
+				Authorization: `Bearer ${token}`,
+			},
+		})
+
+		if (!response.ok) {
+			throw new Error(`WeatherKit API error: ${response.status} ${response.statusText}`)
+		}
+
+		const json = await response.json()
+		const result = weatherKitResponseSchema(json)
+
+		if (result instanceof type.errors) {
+			throw new Error(`WeatherKit API response validation failed: ${result.summary}`)
+		}
+
+		return result
+	}
+}
+
 export const Severity = {
 	Minor: "minor",
 	Moderate: "moderate",