['exception'], 'just one argument is okay' => ['123.00', 123], 'null second argument' => ['123', 123, null], 'false second argument' => ['123', 123, false], 'true second argument' => ['123.0', 123, true], 'fixed decimals without thousands separator' => ['1507.50', 1507.5, 2, true], 'fixed decimals with thousands separator' => ['1,507.50', 1507.5, 2, false], ];