feat: Add OfacFileService

- Add initial OfacFileService including deps
- Added Moq and MockHttp as dependencies
  for testing

src/SanctionsSearch.Worker.Tests/Unit/OfacFileServiceTests.cs

@@ -0,0 +1,62 @@
+using Moq;
+
+using RichardSzalay.MockHttp;
+
+namespace SanctionsSearch.Worker.Tests.Unit;
+
+public class OfacFileServiceTests
+{
+  private readonly MockHttpMessageHandler _mockHttp = new();
+  private readonly Mock<ILogger<OfacFileService>> _mockLogger = new();
+  private readonly Mock<IOptionsSnapshot<OfacFileServiceOptions>> _mockOptions = new();
+
+  [Fact]
+  public void Constructor_WhenCalledWithNullClient_ThrowsArgumentNullException()
+  {
+    var act = () => new OfacFileService(
+      null!,
+      _mockLogger.Object,
+      _mockOptions.Object
+    );
+
+    act.Should().Throw<ArgumentNullException>();
+  }
+
+  [Fact]
+  public void Constructor_WhenCalledWithNullLogger_ThrowsArgumentNullException()
+  {
+    var act = () => new OfacFileService(
+      _mockHttp.ToHttpClient(),
+      null!,
+      _mockOptions.Object
+    );
+
+    act.Should().Throw<ArgumentNullException>();
+  }
+
+  [Fact]
+  public void Constructor_WhenCalledWithNullOptions_ThrowsArgumentNullException()
+  {
+    var act = () => new OfacFileService(
+      _mockHttp.ToHttpClient(),
+      _mockLogger.Object,
+      null!
+    );
+
+    act.Should().Throw<ArgumentNullException>();
+  }
+
+  [Fact]
+  public void Constructor_WhenCalledWithNullOptionsValue_ThrowsArgumentNullException()
+  {
+    _mockOptions.Setup(x => x.Value).Returns(() => null!);
+
+    var act = () => new OfacFileService(
+      _mockHttp.ToHttpClient(),
+      _mockLogger.Object,
+      _mockOptions.Object
+    );
+
+    act.Should().Throw<ArgumentNullException>();
+  }
+}