Ruby Markup Content Model: if a ruby annotation range consists of an rtc element that contains no rt elements, the single ruby annotation unit represented by its contents spans (is paired with) every ruby base unit in the ruby segment.

The example below consists of 2 base characters (今日), jointly annotated with their pronunciation (きょう). For ease of comparison, it is preceded by some context text: “例文は”. This test passes if:

the base characters are presented inline with and similarly to the context text, as if they are all part of the same sentence, and
the annotation is presented as an annotation, and
the annotation is jointly associated with the whole base, not just part of it.

Note: This is not a layout or rendering test. The precise appearance is not specified, and implementations may therefore validly vary.

例文は今日きょう