How to use the flexx.ui.compile.py2js function in flexx

def test_print(self):
        # Test code
        assert py2js('print()') == 'console.log();'
        assert py2js('print(3)') == 'console.log(3);'
        assert py2js('foo.print()') == 'foo.print();'
        
        # Test single
        assert evalpy('print(3)') == '3'
        assert evalpy('print(3); print(3)') == '3\n3'
        assert evalpy('print(); print(3)') == '\n3'  # Test \n
        assert evalpy('print("hello world")') == 'hello world'
        # Test multiple args
        assert evalpy('print(3, "hello")') == '3 hello'
        assert evalpy('print(3+1, "hello", 3+1)') == '4 hello 4'
        # Test sep and end
        assert evalpy('print(3, 4, 5)') == '3 4 5'
        assert evalpy('print(3, 4, 5, sep="")') == '345'
        assert evalpy('print(3, 4, 5, sep="\\n")') == '3\n4\n5'
        assert evalpy('print(3, 4, 5, sep="--")') == '3--4--5'
        assert evalpy('print(3, 4, 5, end="-")') == '3 4 5-'

def test_var_args3(self):
        code1 = 'var x = ' + self.method3.js.jscode
        lines = [line for line in code1.split('\n') if line]
        
        code2 = py2js('x(2, 3)')
        assert evaljs(code1 + code2, False) == '[2,3]'
        code2 = py2js('x()')
        assert evaljs(code1 + code2, False) == '[]'
        code2 = py2js('a=[2,3]\nx(*a)')
        assert evaljs(code1 + code2, False) == '[2,3]'
        code2 = py2js('a=[2,3]\nx(1,2,*a)')
        assert evaljs(code1 + code2, False) == '[1,2,2,3]'

def test_ops(self):
        # Test code
        assert py2js('2+3') == '2 + 3;'  # Binary
        assert py2js('2/3') == '2 / 3;'
        assert py2js('not 2') == '!2;'  # Unary
        assert py2js('-(2+3)') == '-(2 + 3);'
        assert py2js('True and False') == 'true && false;'  # Boolean
        assert py2js('4 > 3') == '4 > 3;'  # Comparisons
        assert py2js('4 is 3') == '4 === 3;'
        
        # No parentices around names, numbers and strings
        assert py2js('foo + bar') == "foo + bar;"
        assert py2js('_foo3 + _bar4') == "_foo3 + _bar4;"
        assert py2js('3 + 4') == "3 + 4;"
        assert py2js('"abc" + "def"') == "'abc' + 'def';"
        assert py2js("'abc' + 'def'") == "'abc' + 'def';"
        assert py2js("'abc' + \"'def\"") == "'abc' + \"'def\";"
        
        # But they should be if it gets more complex
        assert py2js('foo + bar == 3') == "(foo + bar) == 3;"

def test_assignments(self):
        assert py2js('foo = 3') == 'var foo = 3;'  # with var
        assert py2js('foo.bar = 3') == 'foo.bar = 3;'  # without var
        
        code = py2js('foo = 3; bar = 4')  # define both
        assert code.count('var') == 2
        code = py2js('foo = 3; foo = 4')  # only define first time
        assert code.count('var') == 1
        
        code = py2js('foo = bar = 3')  # multiple assignment
        assert 'foo = bar = 3' in code
        assert 'var foo, bar' in code
        
        # self -> this
        assert py2js('self') == 'this;'
        assert py2js('self.foo') == 'this.foo;'
        
        # Indexing
        assert evalpy('a=[0,0]\na[0]=2\na[1]=3\na', False) == '[2,3]'

def test_basic_types(self):
        assert py2js('True') == 'true;'
        assert py2js('False') == 'false;'
        assert py2js('None') == 'null;'
        
        assert py2js('"bla\\"bla"') == "'bla\"bla';"
        assert py2js('3') == '3;'
        assert py2js('3.1415') == '3.1415;'
        
        assert py2js('[1,2,3]') == '[1, 2, 3];'
        assert py2js('{foo: 3, bar: 4}') == '{foo: 3, bar: 4};'

assert ' in ' not in py2js('for i in {1:2, 2:3}: pass')
        
        # Test declaration of iteration variable
        assert 'var i;' in py2js('for i in x: pass')
        assert 'var i' in py2js('i=""\nfor i in x: pass')
        assert 'var i' not in py2js('j=i=""\nfor i in x: pass')
        
        # Test output for range
        assert evalpy('for i in range(3):\n  print(i)') == '0\n1\n2'
        assert evalpy('for i in range(1,6,2):\n  print(i)') == '1\n3\n5'
        
        # Test explicit for-array iteration
        code = py2js('a=[7,8]\nfor i in range(len(a)):\n  print(a[i])')
        assert ' in ' not in code and evaljs(code) == '7\n8'
        # Test enumeration over arrays - should use actual for-loop
        code = py2js('for k in [7, 8]:\n  print(k)')
        assert ' in ' not in code and evaljs(code) == '7\n8'
        
        # Test enumeration over dicts 
        # Python cannot see its a dict, and uses a for-loop
        code = py2js('d = {3:7, 4:8}\nfor k in d:\n  print(k)')
        assert ' in ' not in code and evaljs(code) == '3\n4'
        code = py2js('d = {3:7, 4:8}\nfor k in d:\n  print(d[k])')
        assert ' in ' not in code and evaljs(code) == '7\n8'
        # .keys()
        code = py2js('d = {3:7, 4:8}\nfor k in d.keys():\n  print(d[k])')
        assert ' in ' in code and evaljs(code) == '7\n8'
        # .values()
        code = py2js('d = {3:7, 4:8}\nfor v in d.values():\n  print(v)')
        assert ' in ' in code and evaljs(code) == '7\n8'
        # .items()
        code = py2js('d = {3:7, 4:8}\nfor k,v in d.items():\n  print(k)')

def test_ops(self):
        # Test code
        assert py2js('2+3') == '2 + 3;'  # Binary
        assert py2js('2/3') == '2 / 3;'
        assert py2js('not 2') == '!2;'  # Unary
        assert py2js('-(2+3)') == '-(2 + 3);'
        assert py2js('True and False') == 'true && false;'  # Boolean
        assert py2js('4 > 3') == '4 > 3;'  # Comparisons
        assert py2js('4 is 3') == '4 === 3;'
        
        # No parentices around names, numbers and strings
        assert py2js('foo + bar') == "foo + bar;"
        assert py2js('_foo3 + _bar4') == "_foo3 + _bar4;"
        assert py2js('3 + 4') == "3 + 4;"
        assert py2js('"abc" + "def"') == "'abc' + 'def';"
        assert py2js("'abc' + 'def'") == "'abc' + 'def';"
        assert py2js("'abc' + \"'def\"") == "'abc' + \"'def\";"
        
        # But they should be if it gets more complex
        assert py2js('foo + bar == 3') == "(foo + bar) == 3;"
        
        # Test outcome
        assert evalpy('2+3') == '5'  # Binary
        assert evalpy('6/3') == '2'
        assert evalpy('4//3') == '1'
        assert evalpy('2**8') == '256'
        assert evalpy('not True') == 'false'  # Unary
        assert evalpy('- 3') == '-3'
        assert evalpy('True and False') == 'false'  # Boolean

def test_assignments(self):
        assert py2js('foo = 3') == 'var foo = 3;'  # with var
        assert py2js('foo.bar = 3') == 'foo.bar = 3;'  # without var
        
        code = py2js('foo = 3; bar = 4')  # define both
        assert code.count('var') == 2
        code = py2js('foo = 3; foo = 4')  # only define first time
        assert code.count('var') == 1
        
        code = py2js('foo = bar = 3')  # multiple assignment
        assert 'foo = bar = 3' in code
        assert 'var foo, bar' in code
        
        # self -> this
        assert py2js('self') == 'this;'
        assert py2js('self.foo') == 'this.foo;'
        
        # Indexing
        assert evalpy('a=[0,0]\na[0]=2\na[1]=3\na', False) == '[2,3]'

def test_ops(self):
        # Test code
        assert py2js('2+3') == '2 + 3;'  # Binary
        assert py2js('2/3') == '2 / 3;'
        assert py2js('not 2') == '!2;'  # Unary
        assert py2js('-(2+3)') == '-(2 + 3);'
        assert py2js('True and False') == 'true && false;'  # Boolean
        assert py2js('4 > 3') == '4 > 3;'  # Comparisons
        assert py2js('4 is 3') == '4 === 3;'
        
        # No parentices around names, numbers and strings
        assert py2js('foo + bar') == "foo + bar;"
        assert py2js('_foo3 + _bar4') == "_foo3 + _bar4;"
        assert py2js('3 + 4') == "3 + 4;"
        assert py2js('"abc" + "def"') == "'abc' + 'def';"
        assert py2js("'abc' + 'def'") == "'abc' + 'def';"
        assert py2js("'abc' + \"'def\"") == "'abc' + \"'def\";"
        
        # But they should be if it gets more complex
        assert py2js('foo + bar == 3') == "(foo + bar) == 3;"
        
        # Test outcome
        assert evalpy('2+3') == '5'  # Binary
        assert evalpy('6/3') == '2'
        assert evalpy('4//3') == '1'
        assert evalpy('2**8') == '256'
        assert evalpy('not True') == 'false'  # Unary
        assert evalpy('- 3') == '-3'
        assert evalpy('True and False') == 'false'  # Boolean
        assert evalpy('True or False') == 'true'

def test_ops(self):
        # Test code
        assert py2js('2+3') == '2 + 3;'  # Binary
        assert py2js('2/3') == '2 / 3;'
        assert py2js('not 2') == '!2;'  # Unary
        assert py2js('-(2+3)') == '-(2 + 3);'
        assert py2js('True and False') == 'true && false;'  # Boolean
        assert py2js('4 > 3') == '4 > 3;'  # Comparisons
        assert py2js('4 is 3') == '4 === 3;'
        
        # No parentices around names, numbers and strings
        assert py2js('foo + bar') == "foo + bar;"
        assert py2js('_foo3 + _bar4') == "_foo3 + _bar4;"
        assert py2js('3 + 4') == "3 + 4;"
        assert py2js('"abc" + "def"') == "'abc' + 'def';"
        assert py2js("'abc' + 'def'") == "'abc' + 'def';"
        assert py2js("'abc' + \"'def\"") == "'abc' + \"'def\";"
        
        # But they should be if it gets more complex
        assert py2js('foo + bar == 3') == "(foo + bar) == 3;"
        
        # Test outcome
        assert evalpy('2+3') == '5'  # Binary
        assert evalpy('6/3') == '2'
        assert evalpy('4//3') == '1'
        assert evalpy('2**8') == '256'
        assert evalpy('not True') == 'false'  # Unary
        assert evalpy('- 3') == '-3'