Add Equatable conformance for RedisError

Motivation:

There is a reasonable way to compare if two `RedisErrors` are equal, which was seen as needed in the `Equatable` conformance for `RESPValue`.

Modifications:

Added `Equatable` conformance for `RedisError` by comparing the messages.

Result:

Two `RedisError` instances are now equatable.

Author: Mordil

Sources/RediStack/RESP/RESPValue.swift

@@ -138,7 +138,7 @@ extension RESPValue: Equatable {
         case (.bulkString(let lhs), .bulkString(let rhs)): return lhs == rhs
         case (.simpleString(let lhs), .simpleString(let rhs)): return lhs == rhs
         case (.integer(let lhs), .integer(let rhs)): return lhs == rhs
-        case (.error(let lhs), .error(let rhs)): return lhs.message == rhs.message
+        case (.error(let lhs), .error(let rhs)): return lhs == rhs
         case (.array(let lhs), .array(let rhs)): return lhs == rhs
         case (.null, .null): return true
         default: return false

Sources/RediStack/RedisErrors.swift

@@ -37,12 +37,16 @@ public enum RedisClientError: LocalizedError {
 }
 
 /// If something goes wrong with a command within Redis, it will respond with an error that is captured and represented by instances of this type.
-public struct RedisError: LocalizedError {
+public struct RedisError: LocalizedError, Equatable {
     public let message: String
 
     public var errorDescription: String? { return message }
 
     public init(reason: String) {
         message = "Redis: \(reason)"
     }
+    
+    public static func == (lhs: RedisError, rhs: RedisError) -> Bool {
+        return lhs.message == rhs.message
+    }
 }

Tests/RediStackTests/ChannelHandlers/RedisByteDecoderTests.swift

@@ -299,9 +299,3 @@ extension RedisByteDecoderTests {
         return try decoder.decode(context: context, buffer: &buffer)
     }
 }
-
-extension RedisError: Equatable {
-    public static func == (lhs: RedisError, rhs: RedisError) -> Bool {
-        return lhs.message == rhs.message
-    }
-}