diff --git a/.idea/runConfigurations/All_Tests__coverage_.xml b/.idea/runConfigurations/All_Tests__coverage_.xml
deleted file mode 100644
index 8b07c24..0000000
--- a/.idea/runConfigurations/All_Tests__coverage_.xml
+++ /dev/null
@@ -1,12 +0,0 @@
-<component name="ProjectRunConfigurationManager">
-  <configuration default="false" name="All Tests (coverage)" type="JavaScriptTestRunnerJest">
-    <node-interpreter value="project" />
-    <node-options value="" />
-    <jest-package value="$PROJECT_DIR$/node_modules/jest" />
-    <working-dir value="$PROJECT_DIR$" />
-    <jest-options value="--coverage" />
-    <envs />
-    <scope-kind value="ALL" />
-    <method v="2" />
-  </configuration>
-</component>
\ No newline at end of file
diff --git a/screens/Tetris/Piece.js b/screens/Tetris/Piece.js
index 8818d0c..306b9ef 100644
--- a/screens/Tetris/Piece.js
+++ b/screens/Tetris/Piece.js
@@ -21,7 +21,11 @@ export default class Piece {
     #currentShape: Object;
 
     constructor(colors: Object) {
-        this.#currentShape = new this.#shapes[Math.floor(Math.random() * 7)](colors);
+        this.#currentShape = this.getRandomShape(colors);
+    }
+
+    getRandomShape(colors: Object) {
+        return new this.#shapes[Math.floor(Math.random() * 7)](colors);
     }
 
     toGrid(grid: Array<Array<Object>>, isPreview: boolean) {
diff --git a/screens/Tetris/__tests__/Piece.test.js b/screens/Tetris/__tests__/Piece.test.js
new file mode 100644
index 0000000..f750848
--- /dev/null
+++ b/screens/Tetris/__tests__/Piece.test.js
@@ -0,0 +1,109 @@
+import React from 'react';
+import Piece from "../Piece";
+import ShapeI from "../Shapes/ShapeI";
+
+let colors = {
+    tetrisI: "#000001",
+    tetrisBackground: "#000002"
+};
+
+jest.mock("../Shapes/ShapeI");
+
+beforeAll(() => {
+    jest.spyOn(Piece.prototype, 'getRandomShape')
+        .mockImplementation((colors: Object) => {return new ShapeI(colors);});
+});
+
+afterAll(() => {
+    jest.restoreAllMocks();
+});
+
+test('isPositionValid', () => {
+    let x = 0;
+    let y = 0;
+    let spy = jest.spyOn(ShapeI.prototype, 'getCellsCoordinates')
+        .mockImplementation(() => {return [{x: x, y: y}];});
+    let grid = [
+        [{isEmpty: true}, {isEmpty: true}],
+        [{isEmpty: true}, {isEmpty: false}],
+    ];
+    let size = 2;
+
+    let p = new Piece(colors);
+    expect(p.isPositionValid(grid, size, size)).toBeTrue();
+    x = 1; y = 0;
+    expect(p.isPositionValid(grid, size, size)).toBeTrue();
+    x = 0; y = 1;
+    expect(p.isPositionValid(grid, size, size)).toBeTrue();
+    x = 1; y = 1;
+    expect(p.isPositionValid(grid, size, size)).toBeFalse();
+    x = 2; y = 0;
+    expect(p.isPositionValid(grid, size, size)).toBeFalse();
+    x = -1; y = 0;
+    expect(p.isPositionValid(grid, size, size)).toBeFalse();
+    x = 0; y = 2;
+    expect(p.isPositionValid(grid, size, size)).toBeFalse();
+    x = 0; y = -1;
+    expect(p.isPositionValid(grid, size, size)).toBeFalse();
+
+    spy.mockRestore();
+});
+
+test('tryMove', () => {
+    let p = new Piece(colors);
+    const callbackMock = jest.fn();
+    let isValid = true;
+    let spy = jest.spyOn(Piece.prototype, 'isPositionValid')
+        .mockImplementation(() => {return isValid;});
+
+    expect(p.tryMove(-1, 0, null, null, null, callbackMock)).toBeTrue();
+    isValid = false;
+    expect(p.tryMove(-1, 0, null, null, null, callbackMock)).toBeFalse();
+    isValid = true;
+    expect(p.tryMove(0, 1, null, null, null, callbackMock)).toBeTrue();
+    expect(callbackMock).toBeCalledTimes(0);
+
+    isValid = false;
+    expect(p.tryMove(0, 1, null, null, null, callbackMock)).toBeFalse();
+    expect(callbackMock).toBeCalledTimes(1);
+
+    spy.mockRestore();
+});
+
+test('tryRotate', () => {
+    let p = new Piece(colors);
+    let isValid = true;
+    let spy = jest.spyOn(Piece.prototype, 'isPositionValid')
+        .mockImplementation(() => {return isValid;});
+
+    expect(p.tryRotate( null, null, null)).toBeTrue();
+    isValid = false;
+    expect(p.tryRotate( null, null, null)).toBeFalse();
+
+    spy.mockRestore();
+});
+
+
+test('toGrid', () => {
+    let x = 0;
+    let y = 0;
+    let spy1 = jest.spyOn(ShapeI.prototype, 'getCellsCoordinates')
+        .mockImplementation(() => {return [{x: x, y: y}];});
+    let spy2 = jest.spyOn(ShapeI.prototype, 'getColor')
+        .mockImplementation(() => {return colors.tetrisI;});
+    let grid = [
+        [{isEmpty: true}, {isEmpty: true}],
+        [{isEmpty: true}, {isEmpty: true}],
+    ];
+    let expectedGrid = [
+        [{color: colors.tetrisI, isEmpty: false}, {isEmpty: true}],
+        [{isEmpty: true}, {isEmpty: true}],
+    ];
+
+    let p = new Piece(colors);
+    p.toGrid(grid, true);
+    expect(grid).toStrictEqual(expectedGrid);
+
+    spy1.mockRestore();
+    spy2.mockRestore();
+});
diff --git a/screens/Tetris/__tests__/Tetromino.test.js b/screens/Tetris/__tests__/Shape.test.js
similarity index 100%
rename from screens/Tetris/__tests__/Tetromino.test.js
rename to screens/Tetris/__tests__/Shape.test.js