import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.assertEquals;

class TestSubtractString {

    private StringOperator strOp = new StringOperator();

    @Test
    void subtractString() {
        assertEquals("77", strOp.subtractString("6767", "6"));
        assertEquals("66", strOp.subtractString("6767", "7"));
        assertEquals("6767", strOp.subtractString("6767", ""));
        assertEquals("777", strOp.subtractString("666777", "6"));
        assertEquals("67777", strOp.subtractString("6667777", "66"));
        assertEquals("", strOp.subtractString("66667776666", "66667776666"));
        assertEquals("777", strOp.subtractString("66667776666", "6"));
        assertEquals("666676666", strOp.subtractString("66667776666", "77"));
        assertEquals("66666666", strOp.subtractString("66667776666", "777"));
        assertEquals("Hello,  String subtractor!", strOp.subtractString("Hello, dear String subtractor!", "dear"));
        assertEquals(", dear String subtractor!", strOp.subtractString("Hello, dear String subtractor!", "Hello"));
        assertEquals("Hello,  String subtractor!", strOp.subtractString("Hello, DEAR String subtractor!", "dear"));
        assertEquals("Hello,  String subtractor!", strOp.subtractString("Hello, dear String subtractor!", "DEAR"));
        assertEquals("Hello, dear String !", strOp.subtractString("Hello, dear String subtractor!", "subtractor"));
    }
}