wrote test cases for the 3 endpoints based on what they return

Signed-off-by: Matt Bruce <mbrucedogs@gmail.com>

EmployeeDirectoryTests/EmployeeDirectoryTests.swift

@@ -6,17 +6,44 @@
 //
 
 import Testing
+import XCTest
+
 @testable import EmployeeDirectory
 
 struct EmployeeDirectoryTests {
     
     @Test func getEmployeesValid() async throws {
-        let employees = try await EmployeeService().getEmployees()
-        #expect(employees.count == 11)
+        do {
+            let wrapper = try await EmployeeService().getEmployees(.production)
+            #expect(wrapper.employees.count == 11)
+        } catch {
+            XCTFail("Unexpected error: \(error)")
+        }
     }
     
-    @Test func getEmployeesInValid() async throws {
-        let employees = try await EmployeeService().getEmployees()
-        #expect(employees.count == 11)
+    @Test func getEmployeesMalformed() async throws {
+        do {
+            let wrapper = try await EmployeeService().getEmployees(.malformed)
+            XCTFail("Expected to throw, but got \(wrapper.employees.count) employees")
+        } catch let error as NetworkServiceError {
+            switch error {
+            case .invalidResponse:
+                XCTAssertTrue(true, "Correctly threw invalidResponse error")
+            default:
+                XCTFail("Expected NetworkServiceError.invalidResponse, but got \(error)")
             }
+        } catch {
+            XCTFail("Unexpected error: \(error)")
+        }
+    }
+    
+    @Test func getEmployeesEmpty() async throws {
+        do {
+            let wrapper = try await EmployeeService().getEmployees(.empty)
+            #expect(wrapper.employees.count == 0)
+        } catch {
+            XCTFail("Unexpected error: \(error)")
+        }
+    }
+
 }