Update RedisClient.expire to no longer use deadline terminology.

Motivation:

During proposal review, it was appropriately pointed out that `RedisClient.expire` incorrectly mixes 'deadline' and 'timeout' terminology.

Modifications:

- Change references of 'deadline' to 'timeout' to follow Redis' established semantics for 'EXPIRE'
- Add additional unit test for `RedisClient.expire`

Result:

`RedisClient.expire` should now be more clear as to its semantics and not mix terminology incorrectly.

This contributes to issue #47

Author: Mordil

Sources/RedisNIO/Commands/BasicCommands.swift

@@ -84,11 +84,11 @@ extension RedisClient {
     /// [https://redis.io/commands/expire](https://redis.io/commands/expire)
     /// - Parameters:
     ///     - key: The key to set the expiration on.
-    ///     - deadline: The time from now the key will expire at.
+    ///     - timeout: The time from now the key will expire at.
     /// - Returns: `true` if the expiration was set.
     @inlinable
-    public func expire(_ key: String, after deadline: TimeAmount) -> EventLoopFuture<Bool> {
-        let amount = deadline.nanoseconds / 1_000_000_000
+    public func expire(_ key: String, after timeout: TimeAmount) -> EventLoopFuture<Bool> {
+        let amount = timeout.nanoseconds / 1_000_000_000
         return send(command: "EXPIRE", with: [key, amount])
             .convertFromRESPValue(to: Int.self)
             .map { return $0 == 1 }

Tests/RedisNIOTests/Commands/BasicCommandsTests.swift

@@ -60,14 +60,14 @@ final class BasicCommandsTests: XCTestCase {
 
     func test_expire() throws {
         try connection.set(#function, to: "value").wait()
-        let before = try connection.get(#function).wait()
-        XCTAssertNotNil(before)
-
-        let result = try connection.expire(#function, after: .nanoseconds(1)).wait()
-        XCTAssertEqual(result, true)
-
-        let after = try connection.get(#function).wait()
-        XCTAssertNil(after)
+        XCTAssertNotNil(try connection.get(#function).wait())
+        XCTAssertTrue(try connection.expire(#function, after: .nanoseconds(1)).wait())
+        XCTAssertNil(try connection.get(#function).wait())
+        
+        try connection.set(#function, to: "new value").wait()
+        XCTAssertNotNil(try connection.get(#function).wait())
+        XCTAssertTrue(try connection.expire(#function, after: .seconds(10)).wait())
+        XCTAssertNotNil(try connection.get(#function).wait())
     }
 
     func test_ping() throws {