package table;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import static sexpression.Nil.NIL;
import static sexpression.Symbol.T;

import org.junit.Before;
import org.junit.Test;

public class SymbolTableTest {

    private SymbolTable symbolTable;

    @Before
    public void setUp() {
        symbolTable = new SymbolTable();
    }

    @Test
    public void lookupSymbolNotInTable() {
        assertFalse(symbolTable.contains("symbol"));
    }

    @Test
    public void lookupSymbolInTable() {
        symbolTable.put("symbol", T);

        assertTrue(symbolTable.contains("symbol"));
    }

    @Test
    public void retrieveSymbolValue() {
        symbolTable.put("symbol", T);

        assertEquals(T, symbolTable.get("symbol"));
    }

    @Test
    public void redefineSymbolValue() {
        symbolTable.put("symbol", T);
        symbolTable.put("symbol", NIL);

        assertEquals(NIL, symbolTable.get("symbol"));
    }

    @Test
    public void checkParentTableIsCorrect() {
        SymbolTable childTable = new SymbolTable(symbolTable);

        assertEquals(symbolTable, childTable.getParent());
    }

    @Test
    public void lookupSymbolInParentTable() {
        symbolTable.put("symbol", T);
        SymbolTable childTable = new SymbolTable(symbolTable);
        SymbolTable parentTable = childTable.getParent();

        assertEquals(T, parentTable.get("symbol"));
    }

}