diff --git a/src/tests/flows/layout.ts b/src/tests/flows/layout.ts
index 157d95c..24a4d89 100644
--- a/src/tests/flows/layout.ts
+++ b/src/tests/flows/layout.ts
@@ -37,12 +37,15 @@ tests.register("Focus and move windows", 1, () => {
     function testLayout(shortcutName: string, grid: KwinClient[][]) {
         qtMock.fireShortcut(shortcutName);
         const screen = new MockQmlRect(0, 0, screenWidth, screenHeight);
-        Assert.grid(config, screen, grid, 1);
+        Assert.grid(config, screen, grid, { skip: 1 });
     }
 
     function testFocus(shortcutName: string, expectedFocus: KwinClient) {
         qtMock.fireShortcut(shortcutName);
-        Assert.assert(workspaceMock.activeWindow === expectedFocus, `wrong activeWindow: ${workspaceMock.activeWindow?.pid}`, 1);
+        Assert.assert(workspaceMock.activeWindow === expectedFocus, {
+            message: `wrong activeWindow: ${workspaceMock.activeWindow?.pid}`,
+            skip: 1,
+        });
     };
 
     testLayout("karousel-column-move-right",       [ [client1], [client2], [client3] ]);
diff --git a/src/tests/units/rules/WindowRuleEnforcer.ts b/src/tests/units/rules/WindowRuleEnforcer.ts
index c7859d5..3bedd7d 100644
--- a/src/tests/units/rules/WindowRuleEnforcer.ts
+++ b/src/tests/units/rules/WindowRuleEnforcer.ts
@@ -15,7 +15,10 @@ tests.register("WindowRuleEnforcer", 1, () => {
     const enforcer = new WindowRuleEnforcer(JSON.parse(defaultWindowRules));
     for (const testCase of testCases) {
         const kwinClient: any = createKwinClient(testCase.tiledByDefault, testCase.resourceClass, testCase.caption);
-        Assert.assert(enforcer.shouldTile(kwinClient) === testCase.shouldTile, "failed case: " + JSON.stringify(testCase));
+        Assert.assert(
+            enforcer.shouldTile(kwinClient) === testCase.shouldTile,
+            { message: "failed case: " + JSON.stringify(testCase) },
+        );
     }
 
     function createKwinClient(normalWindow: boolean, resourceClass: string, caption: string) {
diff --git a/src/tests/units/world/Clients.ts b/src/tests/units/world/Clients.ts
index a20dbf2..e9f5938 100644
--- a/src/tests/units/world/Clients.ts
+++ b/src/tests/units/world/Clients.ts
@@ -10,7 +10,10 @@ tests.register("Clients.canTileEver", 1, () => {
 
     for (const testCase of testCases) {
         const kwinClient: any = createKwinClient(testCase.clientProperties);
-        Assert.assert(Clients.canTileEver(kwinClient) === testCase.tileable, "failed case: " + JSON.stringify(testCase));
+        Assert.assert(
+            Clients.canTileEver(kwinClient) === testCase.tileable,
+            { message: "failed case: " + JSON.stringify(testCase) },
+        );
     }
 
     function createKwinClient(properties: { resourceClass: string, caption: string }) {
diff --git a/src/tests/utils/Assert.ts b/src/tests/utils/Assert.ts
index a2d31e8..fe17a86 100644
--- a/src/tests/utils/Assert.ts
+++ b/src/tests/utils/Assert.ts
@@ -1,5 +1,13 @@
 namespace Assert {
-    export function assert(assertion: boolean, message?: string, skip: number = 0) {
+    type Options = {
+        message?: string,
+        skip?: number,
+    }
+
+    export function assert(
+        assertion: boolean,
+        { message, skip=0 }: Options = {},
+    ) {
         if (assertion) {
             return;
         }
@@ -31,35 +39,69 @@ namespace Assert {
     Message: ${message}`);
     }
 
-    export function equal(actual: any, expected: any, skip: number = 0) {
+    export function equal(
+        actual: any,
+        expected: any,
+        { message, skip=0 }: Options = {},
+    ) {
         assert(
             expected == actual,
-            buildMessage(actual, expected, "Values not equal"),
-            skip+1
+            {
+                message: buildMessage(actual, expected, "Values not equal", message),
+                skip: skip + 1,
+            },
         );
     }
 
-    export function equalArrays(actual: any[], expected: any[], skip: number = 0) {
+    export function equalArrays(
+        actual: any[],
+        expected: any[],
+        { message, skip=0 }: Options = {},
+    ) {
         assert(
             actual.length === expected.length && actual.every((item, index) => item === expected[index]),
-            buildMessage(actual, expected, "Arrays not equal"),
-            skip+1
+            {
+                message: buildMessage(actual, expected, "Arrays not equal", message),
+                skip: skip + 1,
+            },
         );
     }
 
-    export function equalRects(actual: QmlRect, expected: QmlRect, skip: number = 0) {
+    export function equalRects(
+        actual: QmlRect,
+        expected: QmlRect,
+        { message, skip=0 }: Options = {},
+    ) {
         assert(
             rectEquals(expected, actual),
-            buildMessage(actual, expected, "QmlRect not equal"),
-            skip+1
+            {
+                message: buildMessage(actual, expected, "QmlRect not equal", message),
+                skip: skip + 1,
+            },
         );
     }
 
-    export function rect(actual: QmlRect, x: number, y: number, width: number, height: number, skip: number = 0) {
-        equalRects(actual, new MockQmlRect(x, y, width, height), skip+1);
+    export function rect(
+        actual: QmlRect,
+        x: number,
+        y: number,
+        width: number,
+        height: number,
+        { message, skip=0 }: Options = {},
+    ) {
+        equalRects(
+            actual,
+            new MockQmlRect(x, y, width, height),
+            { message: message, skip: skip+1 },
+        );
     }
 
-    export function grid(config: Config, screen: QmlRect, grid: KwinClient[][], skip: number = 0) {
+    export function grid(
+        config: Config,
+        screen: QmlRect,
+        grid: KwinClient[][],
+        { message, skip=0 }: Options = {},
+    ) {
         // assumes uniformly sized windows within columns of width 100
         function getRectInGrid(column: number, window: number, nColumns: number, nWindows: number) {
             const columnHeight = screen.height - config.gapsOuterTop - config.gapsOuterBottom;
@@ -79,7 +121,11 @@ namespace Assert {
             const nWindows = column.length;
             for (let iWindow = 0; iWindow < nWindows; iWindow++) {
                 const window = column[iWindow];
-                equalRects(window.frameGeometry, getRectInGrid(iColumn, iWindow, nColumns, nWindows), skip+1);
+                equalRects(
+                    window.frameGeometry,
+                    getRectInGrid(iColumn, iWindow, nColumns, nWindows),
+                    { message: message, skip: skip+1 },
+                );
             }
         }
     }