Show relative difference of numbers of queries

Author: mkllnk

lib/rspec/sql.rb

@@ -29,7 +29,7 @@ module Sql; end
         Expected database queries: #{expected}
         Actual database queries:   #{matcher.actual}
 
-        Diff: #{Expectations.differ.diff_as_object(matcher.actual, expected)}
+        Diff: #{diff(matcher.actual, expected)}
 
         Full query log:
 
@@ -57,6 +57,15 @@ def matcher
       @matcher
     end
 
+    def diff(actual, expected)
+      if expected.is_a?(Numeric)
+        change = actual - expected
+        format("%+d", change)
+      else
+        Expectations.differ.diff_as_object(actual, expected)
+      end
+    end
+
     def scribe_queries(&)
       queries = []
 

spec/lib/rspec/sql_spec.rb

@@ -84,16 +84,12 @@
   end
 
   it "prints user-friendly message expecting a number" do
-    message = error_message { expect { User.last }.to query_database 2 }
+    message = error_message { expect { User.last }.to query_database 0 }
     expect(message).to eq <<~TXT
-      Expected database queries: 2
+      Expected database queries: 0
       Actual database queries:   1
 
-      Diff:
-      @@ -1 +1 @@
-      -2
-      +1
-
+      Diff: +1
 
       Full query log:
 
@@ -107,11 +103,7 @@
       Expected database queries: 2
       Actual database queries:   1
 
-      Diff:
-      @@ -1 +1 @@
-      -2
-      +1
-
+      Diff: -1
 
       Full query log: