Test.wikipedia.org is on the main cluster and uses Commons as its shared repository, and allows us to test MediaSearch in a non-Commons production equivalent environment, allowing rapid deployment and testing without requiring a community to be our guinea pig.

However, on test wikipedia, the interface language is given as "test", not as any actual interface language. That's likely a bug with test wikipedia. If we can deal with that error handling in MediaSearch - e.g, see if this language is a valid language - then we can handle it gracefully and provide a default value (English).

(Replicated on test.wikipedia.org)

RangeError: Incorrect locale information provided

at Number.toLocaleString (<anonymous>)
at VueComponent.resultsCount ()

		resultsCount: function () {
			return this.$i18n(
				'mediasearch-results-count',
				this.totalHits[ this.mediaType ].toLocaleString( mw.config.get( 'wgUserLanguage' ) )
			);
		},

Seems we are assuming the value of mw.config.get('wgUserLanguage') is always going to be a valid arg for toLocaleString(). Unfortunately test wiki is returning:

mw.config.get('wgUserLanguage')
"test"

Acceptance Criteria:

• Implement error handling in MediaSearch to determine if the interface language is valid
• Fail gracefully if the language is invalid and default to English
• Determine if there are other production-level issues this uncovers, and create tickets for them