Check response header's value in Postman tests

I finally found the solution:

pm.test("Redirect location is correct", function () {
   pm.response.to.have.header("Location");
   pm.response.to.be.header("Location", "http://example.com/expected-redirect-url");
});

Here is another way of fetching the specific response header in Tests section ...

loc = pm.response.headers.get("Location");

Just in case, if the subsequent request(s) need the specific info, like header value, then you can also store/set it as environment variable as below, and reuse further

pm.environment.set("redirURL", loc);

var loc = null;
pm.test("Collect redirect location", function () {
   pm.response.to.have.header("Location");
   loc = pm.response.headers.get("Location");
   if (loc !== undefined) {
      pm.environment.set("redirURL", loc);
   }
});

The advantage is - the value collected in the variable can be manipulated.

But it all depends on the situation. Like, you might want to extract and pre/post-process the redirect URL.

For example,

While running the test collection, you would like to collect the value in a variable and change it to point to the mock server's host:port.