Add error call back

Author: GitHub-Ram

src/main/kotlin/com/featurevisor/sdk/FeaturevisorError.kt

@@ -1,6 +1,6 @@
 package com.featurevisor.sdk
 
-sealed class FeaturevisorError(message: String) : Throwable(message = message) {
+sealed class FeaturevisorError(message: String, var code: Int = 0) : Throwable(message = message) {
 
     /// Thrown when attempting to init Featurevisor instance without passing datafile and datafileUrl.
     /// At least one of them is required to init the SDK correctly
@@ -12,7 +12,7 @@ sealed class FeaturevisorError(message: String) : Throwable(message = message) {
     /// - Parameters:
     ///   - data: The data being parsed.
     ///   - errorMessage: The message from the error which occured during parsing.
-    class UnparsableJson(val data: String?, errorMessage: String) : FeaturevisorError(errorMessage)
+    class UnparsableJson(val data: String?, errorMessage: String, code: Int = 0) : FeaturevisorError(errorMessage, code)
 
     /// Thrown when attempting to construct an invalid URL.
     /// - Parameter string: The invalid URL string.

src/main/kotlin/com/featurevisor/sdk/Instance+Fetch.kt

@@ -148,7 +148,15 @@ private suspend fun fetchWithRetry(
                     logger?.error("Request failed with message: ${response.message}")
                     delay(retryInterval)
                 } else {
-                    completion(Result.failure(FeaturevisorError.UnparsableJson(responseBodyString, response.message)))
+                    completion(
+                        Result.failure(
+                            FeaturevisorError.UnparsableJson(
+                                responseBodyString,
+                                response.message,
+                                response.code,
+                            )
+                        )
+                    )
                 }
             }
         } catch (e: IOException) {

src/main/kotlin/com/featurevisor/sdk/Instance.kt

@@ -122,7 +122,7 @@ class FeaturevisorInstance private constructor(options: InstanceOptions) {
                             if (refreshInterval != null) startRefreshing()
                         }.onFailure { error ->
                             logger?.error("Failed to fetch datafile: $error")
-                            emitter.emit(ERROR)
+                            emitter.emit(ERROR, error)
                         }
                         cancelFetchRetry()
                     }

src/test/kotlin/com/featurevisor/sdk/EmitterTest.kt

@@ -4,6 +4,7 @@ import com.featurevisor.types.EventName.ACTIVATION
 import com.featurevisor.types.EventName.READY
 import com.featurevisor.types.EventName.REFRESH
 import com.featurevisor.types.EventName.UPDATE
+import com.featurevisor.types.EventName.ERROR
 import com.featurevisor.types.EventName.values
 import io.mockk.every
 import io.mockk.mockk
@@ -24,6 +25,9 @@ class EmitterTest {
     private val activationCallback: Listener = mockk {
         every { this@mockk(emptyArray()) } answers { nothing }
     }
+    private val errorCallback: Listener = mockk {
+        every { this@mockk(any()) } answers { nothing }
+    }
 
     private val systemUnderTest = Emitter()
 
@@ -85,4 +89,15 @@ class EmitterTest {
             activationCallback(any())
         }
     }
+
+    @Test
+    fun `add error listener and confirm it is invoked`() {
+        systemUnderTest.addListener(ERROR, errorCallback)
+
+        systemUnderTest.emit(ERROR, "data")
+
+        verify(exactly = 1) {
+            errorCallback(arrayOf("data"))
+        }
+    }
 }