diff --git a/src/main/java/org/elasticsearch/common/lucene/search/function/FunctionScoreQuery.java b/src/main/java/org/elasticsearch/common/lucene/search/function/FunctionScoreQuery.java
index 19135535c14..b2ef9ca9c0a 100644
--- a/src/main/java/org/elasticsearch/common/lucene/search/function/FunctionScoreQuery.java
+++ b/src/main/java/org/elasticsearch/common/lucene/search/function/FunctionScoreQuery.java
@@ -200,8 +200,13 @@ public class FunctionScoreQuery extends Query {
     }
 
     public static float toFloat(double input) {
-        assert Double.compare(((float) input), input) == 0 || (Math.abs(((float) input) - input) <= 0.001) : "input " + input + " out of float scope for function score";
+        assert deviation(input) <= 0.001 : "input " + input + " out of float scope for function score deviation: " + deviation(input);
         return (float) input;
     }
+    
+    private static double deviation(double input) { // only with assert!
+        float floatVersion = (float)input;
+        return Double.compare(floatVersion, input) == 0 || input == 0.0d ? 0 : 1.d-(floatVersion) / input;
+    }
 
 }
diff --git a/src/test/java/org/elasticsearch/test/integration/search/functionscore/FunctionScorePluginTests.java b/src/test/java/org/elasticsearch/test/integration/search/functionscore/FunctionScorePluginTests.java
index fa655917f5e..51f9bb4018e 100644
--- a/src/test/java/org/elasticsearch/test/integration/search/functionscore/FunctionScorePluginTests.java
+++ b/src/test/java/org/elasticsearch/test/integration/search/functionscore/FunctionScorePluginTests.java
@@ -21,7 +21,6 @@ package org.elasticsearch.test.integration.search.functionscore;
 
 import org.apache.lucene.search.ComplexExplanation;
 import org.apache.lucene.search.Explanation;
-import org.apache.lucene.util.LuceneTestCase;
 import org.elasticsearch.action.ActionFuture;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.action.search.SearchType;
@@ -62,7 +61,6 @@ public class FunctionScorePluginTests extends AbstractNodesTests {
     }
 
     @Test
-    @LuceneTestCase.AwaitsFix(bugUrl = "britta to look into it, it creates a double value that fails the toFloat assertion")
     public void testPlugin() throws Exception {
         ImmutableSettings.Builder settings = settingsBuilder().put("plugin.types", CustomDistanceScorePlugin.class.getName());
         startNode("server1", settings);