sso: normalize provider config via discovery

src/lib/sso/oidc-config.test.ts

@@ -0,0 +1,56 @@
+import { describe, expect, it } from "bun:test";
+import { normalizeOidcProviderConfig, OidcConfigError } from "./oidc-config";
+
+const issuer = "https://auth.example.com";
+
+describe("normalizeOidcProviderConfig", () => {
+  it("returns provided endpoints when complete", async () => {
+    const result = await normalizeOidcProviderConfig(issuer, {
+      clientId: "client",
+      clientSecret: "secret",
+      authorizationEndpoint: "https://auth.example.com/auth",
+      tokenEndpoint: "https://auth.example.com/token",
+      jwksEndpoint: "https://auth.example.com/jwks",
+      userInfoEndpoint: "https://auth.example.com/userinfo",
+      scopes: ["openid", "email"],
+      pkce: false,
+    }, async () => {
+      throw new Error("fetch should not be called when endpoints are provided");
+    });
+
+    expect(result.oidcConfig.authorizationEndpoint).toBe("https://auth.example.com/auth");
+    expect(result.oidcConfig.tokenEndpoint).toBe("https://auth.example.com/token");
+    expect(result.oidcConfig.jwksEndpoint).toBe("https://auth.example.com/jwks");
+    expect(result.oidcConfig.userInfoEndpoint).toBe("https://auth.example.com/userinfo");
+    expect(result.oidcConfig.scopes).toEqual(["openid", "email"]);
+    expect(result.oidcConfig.pkce).toBe(false);
+  });
+
+  it("derives missing fields from discovery", async () => {
+    const fetchMock = async () =>
+      new Response(JSON.stringify({
+        authorization_endpoint: "https://auth.example.com/auth",
+        token_endpoint: "https://auth.example.com/token",
+        jwks_uri: "https://auth.example.com/jwks",
+        userinfo_endpoint: "https://auth.example.com/userinfo",
+        scopes_supported: ["openid", "email", "profile"],
+      }));
+
+    const result = await normalizeOidcProviderConfig(issuer, {
+      clientId: "client",
+      clientSecret: "secret",
+    }, fetchMock);
+
+    expect(result.oidcConfig.authorizationEndpoint).toBe("https://auth.example.com/auth");
+    expect(result.oidcConfig.tokenEndpoint).toBe("https://auth.example.com/token");
+    expect(result.oidcConfig.jwksEndpoint).toBe("https://auth.example.com/jwks");
+    expect(result.oidcConfig.userInfoEndpoint).toBe("https://auth.example.com/userinfo");
+    expect(result.oidcConfig.scopes).toEqual(["openid", "email", "profile"]);
+  });
+
+  it("throws for invalid issuer URL", async () => {
+    await expect(
+      normalizeOidcProviderConfig("not-a-url", {}),
+    ).rejects.toBeInstanceOf(OidcConfigError);
+  });
+});