Add an unit test to reproduce an XMLPRC upload issue

See wordpress-mobile/WordPress-iOS#22659

Author: crazytonyli

WordPressKitTests/Utilities/HTTPRequestBuilderTests.swift

@@ -403,4 +403,16 @@ class HTTPRequestBuilderTests: XCTestCase {
         )
     }
 
+    func testXMLRPCUpload() throws {
+        let file = try XCTUnwrap(Bundle(for: type(of: self)).url(forResource: "me-settings-success", withExtension: "json"))
+        let fileContentBase64 = try Data(contentsOf: file).base64EncodedString()
+        let fileStream = try XCTUnwrap(InputStream(url: file))
+
+        let request = try HTTPRequestBuilder(url: URL(string: "https://w.org/xmlrpc.php")!)
+            .method(.post)
+            .body(xmlrpc: "wp.uploadFile", parameters: ["username", "passowrd", fileStream])
+            .build(encodeBody: true)
+        XCTAssertTrue(request.httpBodyText?.contains(fileContentBase64) == true)
+    }
+
 }