Document AssertJ's satisfies with extractingJsonPathNumberValue

Closes gh-16229

spring-boot-project/spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc

@@ -6983,6 +6983,19 @@ NOTE: JSON helper classes can also be used directly in standard unit tests. To d
 call the `initFields` method of the helper in your `@Before` method if you do not use
 `@JsonTest`.
 
+If you're using Spring Boot's AssertJ-based helpers to assert on a number value
+at a given JSON path, you might not be able to use `isEqualTo` depending on the type.
+Instead, you can use AssertJ's `satisfies` to assert that the value matches the given
+condition. For instance, the following example asserts that the actual number is a float
+value close to `0.15` within an offset of `0.01`.
+
+[source,java,indent=0]
+----
+assertThat(json.write(message))
+    .extractingJsonPathNumberValue("@.test.numberValue")
+    .satisfies((number) -> assertThat(number.floatValue()).isCloseTo(0.15f, within(0.01f)));
+----
+
 
 
 [[boot-features-testing-spring-boot-applications-testing-autoconfigured-mvc-tests]]