feat: make NylasClient and its methods open for mocking (#258)

# Make NylasClient and its methods open for mocking

This PR makes the NylasClient class and its methods open to enable
mocking in tests, addressing issue #257.

## Changes
- Added `open` modifier to NylasClient class
- Made all resource accessor methods (messages, calendars, etc.) open
- Made HTTP execution methods open for comprehensive mocking support

## Testing
These changes are purely related to class and method modifiers to enable
mocking. The changes do not affect runtime behavior and maintain all
existing functionality. The modifications only impact compile-time
characteristics to allow for better testing capabilities.

## Notes
- This change is backward compatible
- No runtime behavior changes
- Enables better testing capabilities for SDK users

Fixes #257

Link to Devin run:
https://app.devin.ai/sessions/f6b8eb21945e4b84a4b26f39136760cd

---------

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: Aaron de Mello <[email protected]>
Co-authored-by: Aaron de Mello <[email protected]>

CHANGELOG.md

@@ -1,6 +1,7 @@
 # Nylas Java SDK Changelog
 
 ### Unreleased
+* Made `NylasClient` and its methods open to enable mocking in tests
 * Added pagination support for folders
 
 ### [2.5.2] - Released 2024-12-02

src/main/kotlin/com/nylas/NylasClient.kt

@@ -26,7 +26,7 @@ import java.util.concurrent.TimeUnit
  * @param httpClientBuilder The builder to use for creating the http client.
  * @param apiUri The URL to use for communicating with the Nylas API.
  */
-class NylasClient(
+open class NylasClient(
   val apiKey: String,
   httpClientBuilder: OkHttpClient.Builder = defaultHttpClient(),
   apiUri: String = DEFAULT_BASE_URL,
@@ -77,79 +77,79 @@ class NylasClient(
    * Access the Applications API
    * @return The Applications API
    */
-  fun applications(): Applications = Applications(this)
+  open fun applications(): Applications = Applications(this)
 
   /**
    * Access the Attachments API
    * @return The Attachments API
    */
-  fun attachments(): Attachments = Attachments(this)
+  open fun attachments(): Attachments = Attachments(this)
 
   /**
    * Access the Auth API
    * @return The Auth API
    */
-  fun auth(): Auth = Auth(this)
+  open fun auth(): Auth = Auth(this)
 
   /**
    * Access the Calendars API
    * @return The Calendars API
    */
-  fun calendars(): Calendars = Calendars(this)
+  open fun calendars(): Calendars = Calendars(this)
 
   /**
    * Access the Connectors API
    * @return The Connectors API
    */
-  fun connectors(): Connectors = Connectors(this)
+  open fun connectors(): Connectors = Connectors(this)
 
   /**
    * Access the Drafts API
    * @return The Drafts API
    */
-  fun drafts(): Drafts = Drafts(this)
+  open fun drafts(): Drafts = Drafts(this)
 
   /**
    * Access the Events API
    * @return The Events API
    */
-  fun events(): Events = Events(this)
+  open fun events(): Events = Events(this)
 
   /**
    * Access the Folders API
    * @return The Folders API
    */
-  fun folders(): Folders = Folders(this)
+  open fun folders(): Folders = Folders(this)
 
   /**
    * Access the Grants API
    * @return The Grants API
    */
-  fun grants(): Grants = Grants(this)
+  open fun grants(): Grants = Grants(this)
 
   /**
    * Access the Messages API
    * @return The Messages API
    */
-  fun messages(): Messages = Messages(this)
+  open fun messages(): Messages = Messages(this)
 
   /**
    * Access the Threads API
    * @return The Threads API
    */
-  fun threads(): Threads = Threads(this)
+  open fun threads(): Threads = Threads(this)
 
   /**
    * Access the Webhooks API
    * @return The Webhooks API
    */
-  fun webhooks(): Webhooks = Webhooks(this)
+  open fun webhooks(): Webhooks = Webhooks(this)
 
   /**
    * Access the Contacts API
    * @return The Contacts API
    */
-  fun contacts(): Contacts = Contacts(this)
+  open fun contacts(): Contacts = Contacts(this)
 
   /**
    * Access the Scheduler API
@@ -160,7 +160,7 @@ class NylasClient(
   /**
    * Get a URL builder instance for the Nylas API.
    */
-  fun newUrlBuilder(): HttpUrl.Builder = apiUri.newBuilder()
+  open fun newUrlBuilder(): HttpUrl.Builder = apiUri.newBuilder()
 
   /**
    * Execute a GET request to the Nylas API.
@@ -171,7 +171,7 @@ class NylasClient(
    * @suppress Not for public use.
    */
   @Throws(AbstractNylasApiError::class, NylasSdkTimeoutError::class)
-  fun <T> executeGet(
+  open fun <T> executeGet(
     path: String,
     resultType: Type,
     queryParams: IQueryParams? = null,
@@ -191,7 +191,7 @@ class NylasClient(
    * @suppress Not for public use.
    */
   @Throws(AbstractNylasApiError::class, NylasSdkTimeoutError::class)
-  fun <T> executePut(
+  open fun <T> executePut(
     path: String,
     resultType: Type,
     requestBody: String? = null,
@@ -213,7 +213,7 @@ class NylasClient(
    * @suppress Not for public use.
    */
   @Throws(AbstractNylasApiError::class, NylasSdkTimeoutError::class)
-  fun <T> executePatch(
+  open fun <T> executePatch(
     path: String,
     resultType: Type,
     requestBody: String? = null,
@@ -235,7 +235,7 @@ class NylasClient(
    * @suppress Not for public use.
    */
   @Throws(AbstractNylasApiError::class, NylasSdkTimeoutError::class)
-  fun <T> executePost(
+  open fun <T> executePost(
     path: String,
     resultType: Type,
     requestBody: String? = null,
@@ -259,7 +259,7 @@ class NylasClient(
    * @suppress Not for public use.
    */
   @Throws(AbstractNylasApiError::class, NylasSdkTimeoutError::class)
-  fun <T> executeDelete(
+  open fun <T> executeDelete(
     path: String,
     resultType: Type,
     queryParams: IQueryParams? = null,
@@ -280,7 +280,7 @@ class NylasClient(
    * @suppress Not for public use.
    */
   @Throws(AbstractNylasApiError::class, NylasSdkTimeoutError::class)
-  fun <T> executeFormRequest(
+  open fun <T> executeFormRequest(
     path: String,
     method: HttpMethod,
     requestBody: RequestBody,
@@ -324,7 +324,7 @@ class NylasClient(
    * @suppress Not for public use.
    */
   @Throws(AbstractNylasApiError::class, NylasSdkTimeoutError::class)
-  fun <T> executeRequest(
+  open fun <T> executeRequest(
     url: HttpUrl.Builder,
     method: HttpMethod,
     body: RequestBody?,
@@ -339,7 +339,7 @@ class NylasClient(
   }
 
   @Throws(AbstractNylasApiError::class, NylasSdkTimeoutError::class)
-  fun downloadResponse(
+  open fun downloadResponse(
     path: String,
     queryParams: IQueryParams? = null,
     overrides: RequestOverrides? = null,