This test checks a few Number.toPrecision cases, including 15145: (0.999).toPrecision(1) returns incorrect result. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS (0.999).toPrecision(1) is "1" PASS (0.999).toPrecision(2) is "1.0" PASS (0.999).toPrecision(3) is "0.999" PASS (0.0).toPrecision(4) is "0.000" PASS (-0.0).toPrecision(4) is "0.000" PASS (0.0).toPrecision() is "0" PASS (-0.0).toPrecision() is "0" PASS (1234.567).toPrecision() is "1234.567" PASS (1234.567).toPrecision(0) threw exception RangeError: toPrecision() argument must be between 1 and 21. PASS (1234.567).toPrecision(null) threw exception RangeError: toPrecision() argument must be between 1 and 21. PASS (1234.567).toPrecision(false) threw exception RangeError: toPrecision() argument must be between 1 and 21. PASS (1234.567).toPrecision('foo') threw exception RangeError: toPrecision() argument must be between 1 and 21. PASS (1234.567).toPrecision(-1) threw exception RangeError: toPrecision() argument must be between 1 and 21. PASS (1234.567).toPrecision(1) is "1e+3" PASS (1234.567).toPrecision(true) is "1e+3" PASS (1234.567).toPrecision('1') is "1e+3" PASS (1234.567).toPrecision(2) is "1.2e+3" PASS (1234.567).toPrecision(2.9) is "1.2e+3" PASS (1234.567).toPrecision(5) is "1234.6" PASS (1234.567).toPrecision(21) is "1234.56700000000000728" PASS (1234.567).toPrecision(22) threw exception RangeError: toPrecision() argument must be between 1 and 21. PASS (1234.567).toPrecision(100) threw exception RangeError: toPrecision() argument must be between 1 and 21. PASS (1234.567).toPrecision(101) threw exception RangeError: toPrecision() argument must be between 1 and 21. PASS (1234.567).toPrecision(posInf) threw exception RangeError: toPrecision() argument must be between 1 and 21. PASS (1234.567).toPrecision(negInf) threw exception RangeError: toPrecision() argument must be between 1 and 21. PASS (1234.567).toPrecision(nan) threw exception RangeError: toPrecision() argument must be between 1 and 21. PASS posInf.toPrecision() is "Infinity" PASS negInf.toPrecision() is "-Infinity" PASS nan.toPrecision() is "NaN" PASS successfullyParsed is true TEST COMPLETE