### Question:
Version { public static String getBuildNumber(String version) { Matcher qualifierMatcher = qualifierPattern.matcher( getQualifier( version ) ); if( qualifierMatcher.matches() && !isEmpty( qualifierMatcher.group( 4 ) ) ) { return qualifierMatcher.group( 4 ); } return EMPTY_STRING; } private  Version(); static String getBuildNumber(String version); static int getBuildNumberPadding( int incrementalSerialSuffixPadding, Set<String> versions ); static String getMMM(String version); static String getOsgiVersion(String version); static String getQualifier(String version); static String getQualifierBase(String version); static String getQualifierWithDelim(String version); static String getSnapshot( String version ); static String getSnapshotWithDelim( String version ); static boolean hasBuildNumber( String version ); static boolean hasQualifier( String version ); static boolean isEmpty( String string ); static boolean isSnapshot( String version ); static boolean isValidOSGi(String version); static String removeBuildNumber( String version ); static String removeSnapshot( String version ); static String appendQualifierSuffix( final String version, final String suffix ); static String setBuildNumber( String version, String buildNumber ); static String setSnapshot( String version, boolean snapshot ); static int findHighestMatchingBuildNumber(String version, Set<String> versionSet ); static int getIntegerBuildNumber( String version ); static final String PROJECT_VERSION; }### Answer:
@Test public void testGetBuildNumber() { assertThat( Version.getBuildNumber( "1.0-SNAPSHOT" ), equalTo( "" ) ); assertThat( Version.getBuildNumber( "1.0.0.Beta1" ), equalTo( "1" ) ); assertThat( Version.getBuildNumber( "1.0.beta.1-2" ), equalTo( "2" ) ); assertThat( Version.getBuildNumber( "Beta3" ), equalTo( "3" ) ); assertThat( Version.getBuildNumber( "1.x.2.beta4t" ), equalTo( "" ) ); assertThat( Version.getBuildNumber( "1.0.0.Beta11-SNAPSHOT" ), equalTo( "11" ) ); assertThat( Version.getBuildNumber( "1.0.0.Beta1-SNAPSHOT-10" ), equalTo( "10" ) ); }