Sputnik was a JavaScript conformance test suite.

The purpose of the test suite was to determine how well a JavaScript implementation adheres to the ECMA-262 specification, 5th edition, looking only at those features that were also present in the 3rd edition.

[1] It contained over 5000 tests that touched all aspects of the JavaScript language.

[1][2] The test was created in Russia for testing the conformance of the V8 JavaScript engine used in Google Chrome.

Some Sputnik tests however have been found to have issues and do not conform to ECMAScript 5th edition specification.