- to[.not].be.within
The within assertion supports the following forms:
within (min, max, constraint="[]");
within (range);
For example,
expect(5).to.be.within(1, 10);
Equivalently, and more clearly, one can use mathematical notation to indicate the open/closed-ness of the extrema:
expect(5).to.be.within('[1,10]'); // closed/closed or 1 <= 5 <= 10
In this notation, a closed minimum uses "[" and a closed maximum uses "]" as shown above. An open minimum uses "(" while an open maximum uses ")". Closed extrema are consider "in" the range, while open extrema are not.
For example, a commonly useful form of geometric ranges is open/closed:
expect(5).to.be.within('[1,10)'); // 1 <= 5 < 10
The constraint string is simply the notation without the values:
"[]"for closed/closed"[)"for closed/open"(]"for open/closed"()"for open/open
This form is useful when the extrema are known in variable form:
expect(z).to.be.within(x, y, '[)'); // x <= z < y