diff --git a/js/widgets/__tests__/aiwidget.test.js b/js/widgets/__tests__/aiwidget.test.js
new file mode 100644
index 0000000000..1bf4c549a8
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+++ b/js/widgets/__tests__/aiwidget.test.js
@@ -0,0 +1,303 @@
+/**
+ * MusicBlocks
+ *
+ * @author kh-ub-ayb
+ *
+ * @copyright 2026 kh-ub-ayb
+ *
+ * @license
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+const fs = require("fs");
+const path = require("path");
+
+// Load the AIWidget class by reading the source and evaluating it
+// We inject a global setter so tests can access the closure's midiBuffer
+const source = fs.readFileSync(path.resolve(__dirname, "../aiwidget.js"), "utf-8");
+new Function(
+    source.replace(
+        "let midiBuffer;",
+        "let midiBuffer; global.mockMidiBuffer = function(m) { midiBuffer = m; };"
+    ) + "\nif (typeof global !== 'undefined') { global.AIWidget = AIWidget; }"
+)();
+
+// Mock globals
+global._ = str => str;
+global.docById = jest.fn(id => document.createElement("div"));
+global.DOUBLEFLAT = "doubleflat";
+global.FLAT = "flat";
+global.NATURAL = "natural";
+global.SHARP = "sharp";
+global.DOUBLESHARP = "doublesharp";
+global.CUSTOMSAMPLES = [];
+global.wheelnav = jest.fn();
+global.getVoiceSynthName = jest.fn(() => "mockSynth");
+global.Singer = jest.fn();
+global.DRUMS = {};
+global.Tone = { Analyser: jest.fn() };
+global.instruments = { 0: { "electronic synth": { connect: jest.fn() } } };
+global.slicePath = jest.fn();
+global.platformColor = jest.fn();
+global.ABCJS = {
+    renderAbc: jest.fn(() => [{ millisecondsPerMeasure: () => 1000 }]),
+    synth: {
+        supportsAudio: jest.fn(() => true),
+        CreateSynth: jest.fn().mockImplementation(() => ({
+            init: jest.fn().mockResolvedValue(),
+            prime: jest.fn().mockResolvedValue(),
+            start: jest.fn(),
+            stop: jest.fn()
+        }))
+    },
+    parseOnly: jest.fn(() => [])
+};
+
+describe("AIWidget", () => {
+    let mockActivity;
+    let mockWidgetWindow;
+
+    beforeEach(() => {
+        document.body.innerHTML = "";
+        jest.clearAllMocks();
+
+        mockWidgetWindow = {
+            clear: jest.fn(),
+            show: jest.fn(),
+            onclose: null,
+            onmaximize: null,
+            addButton: jest.fn(() => {
+                const btn = document.createElement("button");
+                return btn;
+            }),
+            getWidgetBody: jest.fn(() => {
+                const body = document.createElement("div");
+                body.getBoundingClientRect = () => ({ width: 800, height: 600 });
+                return body;
+            }),
+            getWidgetFrame: jest.fn(() => {
+                const frame = document.createElement("div");
+                frame.getBoundingClientRect = () => ({ width: 800, height: 600 });
+                return frame;
+            }),
+            sendToCenter: jest.fn(),
+            isMaximized: jest.fn(() => false),
+            destroy: jest.fn()
+        };
+
+        window.widgetWindows = {
+            windowFor: jest.fn(() => mockWidgetWindow)
+        };
+
+        mockActivity = {
+            logo: {
+                synth: {
+                    loadSynth: jest.fn(),
+                    trigger: jest.fn()
+                }
+            },
+            textMsg: jest.fn(),
+            errorMsg: jest.fn(),
+            blocks: {
+                loadNewBlocks: jest.fn()
+            }
+        };
+
+        const canvas = document.createElement("canvas");
+        document.body.appendChild(canvas);
+
+        const audioError = document.createElement("div");
+        audioError.className = "audio-error";
+        document.body.appendChild(audioError);
+
+        const stopAudio = document.createElement("button");
+        stopAudio.className = "stop-audio";
+        document.body.appendChild(stopAudio);
+    });
+
+    describe("Constructor and Properties", () => {
+        test("Initializes basic properties", () => {
+            const aiwidget = new AIWidget();
+
+            expect(aiwidget.sampleName).toBe("electronic synth");
+            expect(aiwidget.sampleData).toBe("");
+            expect(aiwidget.samplePitch).toBe("sol");
+            expect(aiwidget.sampleOctave).toBe("4");
+            expect(aiwidget.pitchCenter).toBe(9);
+            expect(aiwidget.accidentalCenter).toBe(2);
+            expect(aiwidget.octaveCenter).toBe(4);
+            expect(aiwidget.sampleLength).toBe(1000);
+            expect(aiwidget.pitchAnalysers).toEqual({});
+        });
+    });
+
+    describe("State Modifiers", () => {
+        let aiwidget;
+
+        beforeEach(() => {
+            aiwidget = new AIWidget();
+        });
+
+        test("_usePitch updates pitchCenter", () => {
+            aiwidget._usePitch("sol");
+            expect(aiwidget.pitchCenter).toBe(4);
+
+            aiwidget._usePitch("unknown");
+            expect(aiwidget.pitchCenter).toBe(0); // Fallback to 0 if not found
+        });
+
+        test("_useAccidental updates accidentalCenter", () => {
+            aiwidget._useAccidental(global.FLAT);
+            expect(aiwidget.accidentalCenter).toBe(1);
+
+            aiwidget._useAccidental("unknown");
+            expect(aiwidget.accidentalCenter).toBe(2); // Fallback to center (natural)
+        });
+
+        test("_useOctave sets octave number", () => {
+            aiwidget._useOctave("5");
+            expect(aiwidget.octaveCenter).toBe(5);
+        });
+    });
+
+    describe("Init Method", () => {
+        test("Sets up widget window and basic dependencies", () => {
+            const aiwidget = new AIWidget();
+
+            // Spy on makeCanvas, reconnectSynthsToAnalyser, and pause
+            jest.spyOn(aiwidget, "makeCanvas").mockImplementation(() => {});
+            jest.spyOn(aiwidget, "reconnectSynthsToAnalyser").mockImplementation(() => {});
+            jest.spyOn(aiwidget, "pause").mockImplementation(() => {});
+
+            aiwidget.init(mockActivity);
+
+            expect(window.widgetWindows.windowFor).toHaveBeenCalledWith(aiwidget, "AI");
+            expect(mockWidgetWindow.clear).toHaveBeenCalled();
+            expect(mockWidgetWindow.show).toHaveBeenCalled();
+            expect(mockWidgetWindow.sendToCenter).toHaveBeenCalledTimes(2);
+            expect(aiwidget.activity).toBe(mockActivity);
+
+            // Play and Export buttons logic
+            expect(mockWidgetWindow.addButton).toHaveBeenCalledTimes(2);
+            expect(aiwidget.reconnectSynthsToAnalyser).toHaveBeenCalled();
+        });
+    });
+
+    describe("Methods and Helpers", () => {
+        let aiwidget;
+
+        beforeEach(() => {
+            aiwidget = new AIWidget();
+            aiwidget.activity = mockActivity;
+        });
+
+        test("getSampleLength checks sample size threshold", () => {
+            aiwidget.sampleData = "A".repeat(1333334);
+            aiwidget.getSampleLength();
+            expect(mockActivity.errorMsg).toHaveBeenCalledWith(
+                "Warning: Sample is bigger than 1MB.",
+                undefined
+            );
+
+            mockActivity.errorMsg.mockClear();
+            aiwidget.sampleData = "A".repeat(1000);
+            aiwidget.getSampleLength();
+            expect(mockActivity.errorMsg).not.toHaveBeenCalled();
+        });
+
+        test("showSampleTypeError triggers error", () => {
+            aiwidget.showSampleTypeError();
+            expect(mockActivity.errorMsg).toHaveBeenCalledWith(
+                "Upload failed: Sample is not a .wav file.",
+                undefined
+            );
+        });
+
+        test("_saveSample calls inner __save method logic", () => {
+            jest.spyOn(aiwidget, "__save").mockImplementation(() => {});
+            aiwidget._saveSample();
+            expect(aiwidget.__save).toHaveBeenCalled();
+        });
+
+        test("_addSample pushes unique names to CUSTOMSAMPLES array", () => {
+            global.CUSTOMSAMPLES = [];
+
+            aiwidget.sampleName = "test_sample_1";
+            aiwidget.sampleData = "data1";
+            aiwidget._addSample();
+
+            expect(global.CUSTOMSAMPLES.length).toBe(1);
+            expect(global.CUSTOMSAMPLES[0]).toEqual(["test_sample_1", "data1"]);
+
+            // Try adding same again, should skip
+            aiwidget._addSample();
+            expect(global.CUSTOMSAMPLES.length).toBe(1);
+        });
+
+        test("reconnectSynthsToAnalyser initializes Analyser and connects synth", () => {
+            aiwidget.originalSampleName = "test_sample_orig";
+            global.instruments = {
+                0: {
+                    "electronic synth": { connect: jest.fn() },
+                    "customsample_test_sample_orig": { connect: jest.fn() }
+                }
+            };
+
+            aiwidget.reconnectSynthsToAnalyser();
+
+            expect(global.Tone.Analyser).toHaveBeenCalledTimes(2);
+            expect(global.instruments[0]["electronic synth"].connect).toHaveBeenCalled();
+            expect(
+                global.instruments[0]["customsample_test_sample_orig"].connect
+            ).toHaveBeenCalled();
+        });
+
+        test("_playSample triggers synth with sample configuration", () => {
+            aiwidget.sampleName = "valid_sample";
+            aiwidget.originalSampleName = "original_name";
+            aiwidget.sampleLength = 2000;
+            jest.spyOn(aiwidget, "reconnectSynthsToAnalyser").mockImplementation(() => {});
+
+            aiwidget._playSample();
+
+            expect(aiwidget.reconnectSynthsToAnalyser).toHaveBeenCalled();
+            expect(mockActivity.logo.synth.trigger).toHaveBeenCalledWith(
+                0,
+                [220],
+                2,
+                "customsample_original_name",
+                null,
+                null,
+                false
+            );
+        });
+
+        test("pause stops the midiBuffer", () => {
+            const stopMock = jest.fn();
+            global.mockMidiBuffer({ stop: stopMock });
+            aiwidget.pause();
+            expect(stopMock).toHaveBeenCalled();
+        });
+
+        test("resume sets isMoving true and updates playBtn", () => {
+            aiwidget.playBtn = document.createElement("button");
+            aiwidget.isMoving = false;
+
+            aiwidget.resume();
+
+            expect(aiwidget.isMoving).toBe(true);
+            expect(aiwidget.playBtn.innerHTML).toContain("pause-button.svg");
+        });
+    });
+});