Added a test.

Tests/ValidatorTests/RemoveDenyListTests.swift

@@ -0,0 +1,47 @@
+// Copyright Dave Verwer, Sven A. Schmidt, and other contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import XCTest
+
+import Foundation
+@testable import ValidatorCore
+
+final class RemoveDenyListTests: XCTestCase {
+
+    func test_processPackageDenyList() throws {
+        let packageList = [
+            "https://example.com/owner1/repo1",
+            "https://example.com/owner1/repo2",
+            "https://example.com/OWNER2/REPO1",
+            "https://example.com/owner2/repo2",
+            "https://example.com/owner2/repo3"
+        ].map { PackageURL(rawValue: URL(string: $0)!) }
+
+        let denyList = [
+            "https://example.com/owner1/repo1",
+            "https://example.com/owner2/repo1" // Deliberately a different case
+        ].map { PackageURL(rawValue: URL(string: $0)!) }
+
+        // MUT
+        let command = Validator.RemoveDenyList()
+        let processedList = command.processPackageDenyList(packageList: packageList, denyList: denyList)
+
+        XCTAssertEqual(processedList, [
+            "https://example.com/owner1/repo2",
+            "https://example.com/owner2/repo2",
+            "https://example.com/owner2/repo3"
+        ].map { PackageURL(rawValue: URL(string: $0)!) })
+    }
+
+}