Fix issue with repeated output

If you used the same name for multiple tests, ie. called them all deny,
you got repeated output.

The test commands needs some refactoring, to split out the utilities and
test them independently. For the moment to get this fix out quickly I've
just added an acceptance test which works but is a little too coupled to
the current output.

acceptance.bats

@@ -69,3 +69,9 @@
   [ "$status" -eq 0 ]
   [[ "$output" != *"[33m"* ]]
 }
+
+@test "Output results only once" {
+  run ./conftest test -p examples/kubernetes/policy examples/kubernetes/deployment.yaml
+  count="${#lines[@]}"
+  [ "$count" -eq 4 ]
+}

pkg/commands/test/test.go

@@ -151,7 +151,7 @@ func processFile(ctx context.Context, fileName string, compiler *ast.Compiler) (
 	return failuresList.ErrorOrNil(), warningsList.ErrorOrNil()
 }
 
-// finds all queries in the compiler supported by the
+// finds all queries in the compiler
 func getRules(ctx context.Context, re *regexp.Regexp, compiler *ast.Compiler) []string {
 
 	var res []string
@@ -160,14 +160,27 @@ func getRules(ctx context.Context, re *regexp.Regexp, compiler *ast.Compiler) []
 		for _, r := range m.Rules {
 			n := r.Head.Name.String()
 			if re.MatchString(n) {
-				res = append(res, n)
+				// the same rule names can be used multiple times, but
+				// we only want to run the query and report results once
+				if !stringInSlice(n, res) {
+					res = append(res, n)
+				}
 			}
 		}
 	}
 
 	return res
 }
 
+func stringInSlice(a string, list []string) bool {
+	for _, b := range list {
+		if b == a {
+			return true
+		}
+	}
+	return false
+}
+
 func makeQuery(rule string) string {
 	return fmt.Sprintf("data.%s.%s", viper.GetString("namespace"), rule)
 }