Update documentation for Platform.version

Update documentation for Platform.version

Add test that Platform.version does start with a valid semver string.

BUG=http://dartbug/22244
R=ricow@google.com

Committed: https://code.google.com/p/dart/source/detail?r=43723

[ricow1, 2015-02-12 12:33:08]

lgtm, take the regexp if you want (I use something similar in the validation
code I run on the bots)

https://codereview.chromium.org/921733002/diff/1/tests/standalone/io/platform...
File tests/standalone/io/platform_test.dart (right):

https://codereview.chromium.org/921733002/diff/1/tests/standalone/io/platform...
tests/standalone/io/platform_test.dart:71: var semver = Platform.version.split('
')[0];
How about:


  RegExp versionRE = new RegExp(r'(\d+)\.(\d+)\.(\d+)(-dev\.(\d+)\.(\d+))?');
  var match = versionRE.firstMatch(version);
  Expect.isNotNull(match);
  // Major
  Expect.isTrue(int.parse(match.group(1)) >= 1);
  // Minor
  Expect.isTrue(int.parse(match.group(2)) >= 0);
  // Patch
  Expect.isTrue(int.parse(match.group(3)) >= 0);
  // Dev
  if (match.group(4) != null) {
    // Dev prerelease minor version
    Expect.isTrue(int.parse(match.group(5)) >= 0);
    // Dev prerelease patch version
    Expect.isTrue(int.parse(match.group(6)) >= 0);
  }

[Søren Gjesse, 2015-02-12 13:02:59]

New patchsets have been uploaded after l-g-t-m from ricow@google.com

[Søren Gjesse, 2015-02-12 13:04:47]

PTAL

Made the testing even more rigirous.

https://codereview.chromium.org/921733002/diff/1/tests/standalone/io/platform...
File tests/standalone/io/platform_test.dart (right):

https://codereview.chromium.org/921733002/diff/1/tests/standalone/io/platform...
tests/standalone/io/platform_test.dart:71: var semver = Platform.version.split('
')[0];
On 2015/02/12 12:33:08, ricow1 wrote:
> How about:
> 
> 
>   RegExp versionRE = new RegExp(r'(\d+)\.(\d+)\.(\d+)(-dev\.(\d+)\.(\d+))?');
>   var match = versionRE.firstMatch(version);
>   Expect.isNotNull(match);
>   // Major
>   Expect.isTrue(int.parse(match.group(1)) >= 1);
>   // Minor
>   Expect.isTrue(int.parse(match.group(2)) >= 0);
>   // Patch
>   Expect.isTrue(int.parse(match.group(3)) >= 0);
>   // Dev
>   if (match.group(4) != null) {
>     // Dev prerelease minor version
>     Expect.isTrue(int.parse(match.group(5)) >= 0);
>     // Dev prerelease patch version
>     Expect.isTrue(int.parse(match.group(6)) >= 0);
>   }

Done.

[ricow1, 2015-02-12 13:12:17]

lgtm

[Søren Gjesse, 2015-02-12 13:36:03]

Committed patchset #2 (id:20001) manually as 43723 (presubmit successful).