diff --git a/SignalServiceKit/Util/StringSanitizerTests.swift b/SignalServiceKit/Util/StringSanitizerTests.swift
index d93838e326..c68f2a7a05 100644
--- a/SignalServiceKit/Util/StringSanitizerTests.swift
+++ b/SignalServiceKit/Util/StringSanitizerTests.swift
@@ -3,126 +3,71 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 //
 
-import XCTest
+import Testing
 @testable import SignalServiceKit
 
-class StringSanitizerTests: XCTestCase {
-    func testEmpty() {
-        let string = ""
-        let sanitized = StringSanitizer.sanitize(string)
-        XCTAssertEqual(sanitized, string)
-    }
-
-    func testASCII() {
-        let string = "abc"
-        let sanitized = StringSanitizer.sanitize(string)
-        XCTAssertEqual(sanitized, string)
-    }
-
-    func testCombiningMarks() {
-        let string = "abx\u{327}c"
-        let sanitized = StringSanitizer.sanitize(string)
-        XCTAssertEqual(sanitized, string)
-    }
-
-    func testEmoji() {
-        let string = "a\u{1f469}\u{1f3ff}\u{200d}\u{2764}\u{fe0f}\u{200d}\u{1f48b}\u{200d}\u{1f469}\u{1f3fb}b"
-        let sanitized = StringSanitizer.sanitize(string)
-        XCTAssertEqual(sanitized, string)
-    }
-
-    func testZalgo() {
-        let string = "x\u{338}\u{306}\u{344}\u{31b}\u{306}\u{33f}\u{344}\u{31a}\u{305}\u{33d}\u{346}\u{35d}\u{344}\u{33f}\u{314}\u{34c}\u{319}\u{31d}\u{322}\u{348}\u{348}\u{316}\u{327}\u{333}\u{317}\u{330}abx\u{338}\u{306}\u{344}\u{31b}\u{306}\u{33f}\u{344}\u{31a}\u{305}\u{33d}\u{346}\u{35d}\u{344}\u{33f}\u{314}\u{34c}\u{319}\u{31d}\u{322}\u{348}\u{348}\u{316}\u{327}\u{333}\u{317}\u{330}x\u{338}\u{306}\u{344}\u{31b}\u{306}\u{33f}\u{344}\u{31a}\u{305}\u{33d}\u{346}\u{35d}\u{344}\u{33f}\u{314}\u{34c}\u{319}\u{31d}\u{322}\u{348}\u{348}\u{316}\u{327}\u{333}\u{317}\u{330}\u{1f469}\u{1f3ff}\u{200d}\u{2764}\u{fe0f}\u{200d}\u{1f48b}\u{200d}\u{1f469}\u{1f3fb}cx\u{338}\u{306}\u{344}\u{31b}\u{306}\u{33f}\u{344}\u{31a}\u{305}\u{33d}\u{346}\u{35d}\u{344}\u{33f}\u{314}\u{34c}\u{319}\u{31d}\u{322}\u{348}\u{348}\u{316}\u{327}\u{333}\u{317}\u{330}"
-        let sanitized = StringSanitizer.sanitize(string)
-        let expected = "\u{fffd}ab\u{fffd}\u{fffd}\u{1f469}\u{1f3ff}\u{200d}\u{2764}\u{fe0f}\u{200d}\u{1f48b}\u{200d}\u{1f469}\u{1f3fb}c\u{fffd}"
-        XCTAssertEqual(sanitized, expected)
-    }
-
-    func testSingleZalgo() {
-        let string = "x\u{338}\u{306}\u{344}\u{31b}\u{306}\u{33f}\u{344}\u{31a}\u{305}\u{33d}\u{346}\u{35d}\u{344}\u{33f}\u{314}\u{34c}\u{319}\u{31d}\u{322}\u{348}\u{348}\u{316}\u{327}\u{333}\u{317}\u{330}"
-        let sanitized = StringSanitizer.sanitize(string)
-        let expected = "\u{fffd}"
-        XCTAssertEqual(sanitized, expected)
-    }
-
-    func testTwoZalgo() {
-        let string = "x\u{338}\u{306}\u{344}\u{31b}\u{306}\u{33f}\u{344}\u{31a}\u{305}\u{33d}\u{346}\u{35d}\u{344}\u{33f}\u{314}\u{34c}\u{319}\u{31d}\u{322}\u{348}\u{348}\u{316}\u{327}\u{333}\u{317}\u{330}x\u{338}\u{306}\u{344}\u{31b}\u{306}\u{33f}\u{344}\u{31a}\u{305}\u{33d}\u{346}\u{35d}\u{344}\u{33f}\u{314}\u{34c}\u{319}\u{31d}\u{322}\u{348}\u{348}\u{316}\u{327}\u{333}\u{317}\u{330}"
-        let sanitized = StringSanitizer.sanitize(string)
-        let expected = "\u{fffd}\u{fffd}"
-        XCTAssertEqual(sanitized, expected)
+struct StringSanitizerTests {
+    @Test(arguments: [
+        ("", nil),
+        ("abc", nil),
+        ("abx\u{327}c", nil),
+        ("a\u{1f469}\u{1f3ff}\u{200d}\u{2764}\u{fe0f}\u{200d}\u{1f48b}\u{200d}\u{1f469}\u{1f3fb}b", nil),
+        (
+            "x\u{338}\u{306}\u{344}\u{31b}\u{306}\u{33f}\u{344}\u{31a}\u{305}\u{33d}\u{346}\u{35d}\u{344}\u{33f}\u{314}\u{34c}\u{319}\u{31d}\u{322}\u{348}\u{348}\u{316}\u{327}\u{333}\u{317}\u{330}abx\u{338}\u{306}\u{344}\u{31b}\u{306}\u{33f}\u{344}\u{31a}\u{305}\u{33d}\u{346}\u{35d}\u{344}\u{33f}\u{314}\u{34c}\u{319}\u{31d}\u{322}\u{348}\u{348}\u{316}\u{327}\u{333}\u{317}\u{330}x\u{338}\u{306}\u{344}\u{31b}\u{306}\u{33f}\u{344}\u{31a}\u{305}\u{33d}\u{346}\u{35d}\u{344}\u{33f}\u{314}\u{34c}\u{319}\u{31d}\u{322}\u{348}\u{348}\u{316}\u{327}\u{333}\u{317}\u{330}\u{1f469}\u{1f3ff}\u{200d}\u{2764}\u{fe0f}\u{200d}\u{1f48b}\u{200d}\u{1f469}\u{1f3fb}cx\u{338}\u{306}\u{344}\u{31b}\u{306}\u{33f}\u{344}\u{31a}\u{305}\u{33d}\u{346}\u{35d}\u{344}\u{33f}\u{314}\u{34c}\u{319}\u{31d}\u{322}\u{348}\u{348}\u{316}\u{327}\u{333}\u{317}\u{330}",
+            "\u{fffd}ab\u{fffd}\u{fffd}\u{1f469}\u{1f3ff}\u{200d}\u{2764}\u{fe0f}\u{200d}\u{1f48b}\u{200d}\u{1f469}\u{1f3fb}c\u{fffd}",
+        ),
+        (
+            "x\u{338}\u{306}\u{344}\u{31b}\u{306}\u{33f}\u{344}\u{31a}\u{305}\u{33d}\u{346}\u{35d}\u{344}\u{33f}\u{314}\u{34c}\u{319}\u{31d}\u{322}\u{348}\u{348}\u{316}\u{327}\u{333}\u{317}\u{330}",
+            "\u{fffd}",
+        ),
+        (
+            "x\u{338}\u{306}\u{344}\u{31b}\u{306}\u{33f}\u{344}\u{31a}\u{305}\u{33d}\u{346}\u{35d}\u{344}\u{33f}\u{314}\u{34c}\u{319}\u{31d}\u{322}\u{348}\u{348}\u{316}\u{327}\u{333}\u{317}\u{330}x\u{338}\u{306}\u{344}\u{31b}\u{306}\u{33f}\u{344}\u{31a}\u{305}\u{33d}\u{346}\u{35d}\u{344}\u{33f}\u{314}\u{34c}\u{319}\u{31d}\u{322}\u{348}\u{348}\u{316}\u{327}\u{333}\u{317}\u{330}",
+            "\u{fffd}\u{fffd}",
+        ),
+    ])
+    func testSanitize(testCase: (original: String, expected: String?)) {
+        #expect(StringSanitizer.sanitize(testCase.original) == (testCase.expected ?? testCase.original))
     }
 }
 
-class StringReplacementTests: XCTestCase {
-
-    func testEquivalent() {
-
-        let testCases: [String: String] = [
-            "": "",
-            " ": "",
-            "         ": "",
-            "a": "a",
-            "abcd": "abcd",
-            " abcd ": "abcd",
-            "abcd ": "abcd",
-            " abcd": "abcd",
-            "ab cd": "abcd",
-            "ab  1 cd ": "ab1cd",
-            "ab            cd ": "abcd",
-        ]
-
-        for key in testCases.keys {
-            let expectedResult = testCases[key]
-
-            let result = key.replaceCharacters(characterSet: .whitespacesAndNewlines, replacement: "")
-
-            XCTAssertEqual(result, expectedResult)
-        }
-    }
-
-    func testEquivalent2() {
-
-        let testCases: [String: String] = [
-            "": "",
-            "abcd": "abcd",
-            " abcd ": "X abcdX ",
-            "abcd ": "abcdX ",
-            " abcd": "X abcd",
-            "ab cd": "abX cd",
-            "ab  1 cd ": "abX X 1X cdX ",
-        ]
-
-        for key in testCases.keys {
-            let expectedResult = testCases[key]
-
-            let result = key.replaceCharacters(characterSet: .whitespacesAndNewlines, replacement: "X ")
-
-            XCTAssertEqual(result, expectedResult)
-        }
-    }
-
-    func testEquivalent3() {
-
-        let testCases: [String: String] = [
-            "": "",
-            "abcd": "",
-            " abcd ": "  ",
-            "abcd ": " ",
-            " abcd": " ",
-            "ab cd": " ",
-            "ab  1 cd ": "  1  ",
-            "ab  1 ZcdX ": "  1 ZX ",
-        ]
-
-        for key in testCases.keys {
-            let expectedResult = testCases[key]
-
-            var characterSetUnion = CharacterSet.punctuationCharacters
-            characterSetUnion.formUnion(.lowercaseLetters)
-
-            let result = key.replaceCharacters(characterSet: characterSetUnion, replacement: "")
-
-            XCTAssertEqual(result, expectedResult)
+struct StringReplacementTests {
+    @Test(arguments: [
+        ("", "", true, ""),
+        (" ", "", true, ""),
+        ("         ", "", true, ""),
+        ("a", "a", true, ""),
+        ("abcd", "abcd", true, ""),
+        (" abcd ", "abcd", true, ""),
+        ("abcd ", "abcd", true, ""),
+        (" abcd", "abcd", true, ""),
+        ("ab cd", "abcd", true, ""),
+        ("ab  1 cd ", "ab1cd", true, ""),
+        ("ab            cd ", "abcd", true, ""),
+        ("", "", true, "X "),
+        ("abcd", "abcd", true, "X "),
+        (" abcd ", "X abcdX ", true, "X "),
+        ("abcd ", "abcdX ", true, "X "),
+        (" abcd", "X abcd", true, "X "),
+        ("ab cd", "abX cd", true, "X "),
+        ("ab  1 cd ", "abX X 1X cdX ", true, "X "),
+        ("", "", false, ""),
+        ("abcd", "", false, ""),
+        (" abcd ", "  ", false, ""),
+        ("abcd ", " ", false, ""),
+        (" abcd", " ", false, ""),
+        ("ab cd", " ", false, ""),
+        ("ab  1 cd ", "  1  ", false, ""),
+        ("ab  1 ZcdX ", "  1 ZX ", false, ""),
+    ])
+    func testEquivalent(testCase: (original: String, expected: String, isWhitespacesAndNewlines: Bool, replacement: String)) {
+        var characterSet: CharacterSet
+        if testCase.isWhitespacesAndNewlines {
+            characterSet = .whitespacesAndNewlines
+        } else {
+            characterSet = .punctuationCharacters
+            characterSet.formUnion(.lowercaseLetters)
         }
+        let result = testCase.original.replaceCharacters(characterSet: characterSet, replacement: testCase.replacement)
+        #expect(result == testCase.expected)
     }
 }