Merge pull request #912 from influxdata/flux/diff-epsilon

Add 'epsilon' and 'verbose' parameters to 'testing.diff'

content/v2.0/reference/flux/stdlib/testing/diff.md

@@ -17,7 +17,11 @@ _**Function type:** Test_
 ```js
 import "testing"
 
-testing.diff(got: stream2, want: stream1)
+testing.diff(
+  got: stream2,
+  want: stream1,
+  epsilon: 0.000000001
+)
 ```
 
 It matches tables from each stream with the same group keys.
@@ -34,16 +38,22 @@ _The `testing.diff()` function can be used to perform in-line diffs in a query._
 ## Parameters
 
 ### got
-The stream containing data to test.
+Stream containing data to test.
 _Defaults to piped-forward data (`<-`)._
 
 _**Data type:** Object_
 
 ### want
-The stream that contains the expected data to test against.
+Stream that contains the expected data to test against.
 
 _**Data type:** Object_
 
+### epsilon
+Specifies how far apart two **float** values can be, but still considered equal.
+Defaults to `0.000000001`.
+
+_**Data type:** Float_
+
 ## Examples
 
 ##### Diff separate streams