Fix close_to assertion (elastic#72187)

Fixes the assertion to actually assert and adds a test to check that it actually does that.

Author: imotov

test/framework/src/main/java/org/elasticsearch/test/rest/yaml/section/CloseToAssertion.java

@@ -68,7 +68,7 @@ public final double getError() {
     protected void doAssert(Object actualValue, Object expectedValue) {
         logger.trace("assert that [{}] is close to [{}] with error [{}] (field [{}])", actualValue, expectedValue, error, getField());
         if (actualValue instanceof Number) {
-            assertThat(((Number) expectedValue).doubleValue(), closeTo((Double) expectedValue, error));
+            assertThat(((Number) actualValue).doubleValue(), closeTo((Double) expectedValue, error));
         } else {
             throw new AssertionError("excpected a value close to " + expectedValue + " but got " + actualValue + ", which is not a number");
         }

test/framework/src/test/java/org/elasticsearch/test/rest/yaml/section/AssertionTests.java

@@ -18,6 +18,7 @@
 import java.util.List;
 import java.util.Map;
 
+import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.notNullValue;
@@ -172,6 +173,15 @@ public void testCloseTo() throws Exception {
         assertThat(closeToAssertion.getExpectedValue(), instanceOf(Double.class));
         assertThat((Double) closeToAssertion.getExpectedValue(), equalTo(42.2));
         assertThat(closeToAssertion.getError(), equalTo(0.001));
+        closeToAssertion.doAssert(42.2 + randomDoubleBetween(-0.001, 0.001, false), closeToAssertion.getExpectedValue());
+        AssertionError e = expectThrows(
+            AssertionError.class,
+            () -> closeToAssertion.doAssert(
+                42.2 + (randomBoolean() ? 1 : -1) * randomDoubleBetween(0.001001, 10, false),
+                closeToAssertion.getExpectedValue()
+            )
+        );
+        assertThat(e.getMessage(), containsString("Expected: a numeric value within <0.001> of <42.2>"));
     }
 
     public void testInvalidCloseTo() throws Exception {