fix: Endpoint url should be nil if host or scheme is missing (#614)

Author: dayaffe

Sources/ClientRuntime/Networking/Endpoint.swift

@@ -63,10 +63,10 @@ extension Endpoint {
     public var url: URL? {
         var components = URLComponents()
         components.scheme = protocolType?.rawValue
-        components.host = host
+        components.host = host.isEmpty ? nil : host // If host is empty, URL is invalid
         components.percentEncodedPath = path
         components.percentEncodedQuery = queryItemString
-        return components.url
+        return (components.host == nil || components.scheme == nil) ? nil : components.url
     }
 
     var queryItemString: String? {

Tests/ClientRuntimeTests/NetworkingTests/HttpRequestTests.swift

@@ -111,7 +111,9 @@ class HttpRequestTests: NetworkingTestUtils {
     }
 
     func testConversionToUrlRequestFailsWithInvalidEndpoint() {
-        // TODO:: When is the endpoint invalid or endpoint.url nil?
-        _ = Endpoint(host: "", path: "", protocolType: nil)
+        // Testing with an invalid endpoint where host is empty,
+        // path is empty, and protocolType is nil.
+        let endpoint = Endpoint(host: "", path: "", protocolType: nil)
+        XCTAssertNil(endpoint.url, "An invalid endpoint should result in a nil URL.")
     }
 }