Tests.Core: add a failure test

Author: Mersho

tests/FSharpLint.Core.Tests/Rules/Conventions/AvoidSinglePipeOperator.fs

@@ -104,3 +104,21 @@ let foo param =
 """
 
         Assert.True this.NoErrorsExist
+
+    [<Test>]
+    member this.``Use pipe operator once on record``() =
+        this.Parse """
+type Person =
+    {
+        FirstName: string
+    }
+
+let someFunc someParam =
+    if someParam then
+        { FirstName = "Bar" } |> someOtherFunc
+    else
+        Array.empty
+"""
+
+        Assert.IsTrue this.ErrorsExist
+