local tdc = table.diffcompare

function unittests.tablecmp()
    -- No differences in these simple-valued tables.
    assert(tdc(nil, {a=true}, nil, {a=true}) == "")
    assert(tdc(nil, {a=5}, nil, {a=5}) == "");
    assert(tdc(nil, {a="foo"}, nil, {a="foo"}) == "")

    -- Test transmission of missing simple values.
    assert(tdc(nil, {a=true}, nil, {}) == "a=true;")
    assert(tdc(nil, {a=5}, nil, {}) == "a=5;");
    assert(tdc(nil, {a="foo"}, nil, {}) == "a=foo;")

    -- Test the replacement of simple values.
    assert(tdc(nil, {a=true}, nil, {a=false}) == "a=true;")
    assert(tdc(nil, {a=5}, nil, {a=4}) == "a=5;");
    assert(tdc(nil, {a="foo"}, nil, {a="bar"}) == "a=foo;")

    -- Test the clearing of values.
    assert(tdc(nil, {}, nil, {a=true}) == "a=nil;")
    assert(tdc(nil, {}, nil, {a=5}) == "a=nil;");
    assert(tdc(nil, {}, nil, {a="foo"}) == "a=nil;")

    -- Try boolean keys.
    assert(tdc(nil, {[true]=3}, nil, {}) == "true=3;")
    assert(tdc(nil, {}, nil, {[true]=3}) == "true=nil;")

    -- Try number keys.
    assert(tdc(nil, {[7]=3}, nil, {}) == "7=3;")
    assert(tdc(nil, {}, nil, {[7]=3}) == "7=nil;")

    -- Try a table with multiple keys.
    assert(tdc(nil, {a=4, b=5, c=6}, nil, {b=5, c=7, d=8}) == "a=4;c=6;d=nil;")

    -- Nonsortable keys should be ignored (no diffs).
    assert(tdc(nil, {[{}]=3}, nil, {}) == "")

    -- Try a table containing a class.
    assert(tdc(nil, {a=deque}, nil, {}) == "a=class deque;")

    -- Try a table containing a pointer to the global environment.
    assert(tdc(nil, {a=_G}, nil, {}) == "a=globals;")

    -- GlobalDB tables should be forced to NIL.
    assert(tdc(nil, {a=global("foo")}, nil, {a=global("foo")}) == "a=nil;");
    assert(tdc(nil, {}, nil, {a=global("foo")}) == "a=nil;");
    assert(tdc(nil, {a=global("foo")}, nil, {}) == "");
    
    -- Set up some numbered tables for tests involving such.
    local mtab10 = {}
    local stab10 = {}
    local mtab11 = {}
    local stab11 = {}
    local mtnmap = {}
    local stnmap = {}
    mtnmap[mtab10] = 10
    stnmap[stab10] = 10
    mtnmap[mtab11] = 11
    stnmap[stab11] = 11

    -- confirm that numbered tables are being transmitted.
    assert(tdc(mtnmap, {a=mtab10}, stnmap, {}) == "a=table 10;")
    assert(tdc(mtnmap, {a=mtab10}, stnmap, {a=stab10}) == "")
    assert(tdc(mtnmap, {a=3}, stnmap, {a=stab10}) == "a=3;")
    assert(tdc(mtnmap, {}, stnmap, {a=stab10}) == "a=nil;")

    -- we're not going to test tangibles
    -- creating tangibles here is too difficult.
end