Better message for suppressed output

checker_test.go

@@ -436,15 +436,15 @@ want:
 }, {
 	about:   "CmpEquals: different values, long output",
 	checker: qt.CmpEquals(),
-	got:     []interface{}{cmpEqualsWant, "extra line 1", "extra line 2"},
+	got:     []interface{}{cmpEqualsWant, "extra line 1", "extra line 2", "extra line 3"},
 	args:    []interface{}{[]interface{}{cmpEqualsWant, "extra line 1"}},
 	expectedCheckFailure: fmt.Sprintf(`
 error:
   values are not deep equal
 diff (-got +want):
 %s
 got:
-  <suppressed because too long, use -v for the full output>
+  <suppressed due to length (11 lines), use -v for full output>
 want:
   []interface {}{
       struct { Strings []interface {}; Ints []int }{
@@ -456,7 +456,7 @@ want:
       },
       "extra line 1",
   }
-`, diff([]interface{}{cmpEqualsWant, "extra line 1", "extra line 2"}, []interface{}{cmpEqualsWant, "extra line 1"})),
+`, diff([]interface{}{cmpEqualsWant, "extra line 1", "extra line 2", "extra line 3"}, []interface{}{cmpEqualsWant, "extra line 1"})),
 }, {
 	about:   "CmpEquals: different values: long output and verbose",
 	checker: qt.CmpEquals(),
@@ -677,9 +677,9 @@ error:
 diff (-got +want):
 %s
 got:
-  <suppressed because too long, use -v for the full output>
+  <suppressed due to length (15 lines), use -v for full output>
 want:
-  <same as "got">
+  <suppressed due to length (16 lines), use -v for full output>
 `, diff([]interface{}{cmpEqualsWant, cmpEqualsWant}, []interface{}{cmpEqualsWant, cmpEqualsWant, 42})),
 }, {
 	about:   "DeepEquals: different values: long output and verbose",

report.go

@@ -73,8 +73,10 @@ func writeError(w io.Writer, err error, p reportParams) {
 			v = string(u)
 		} else if s, ok := value.(SuppressedIfLong); ok {
 			v = p.format(s.Value)
-			if !testingVerbose() && strings.Count(v, "\n") >= longValueLines {
-				v = "<suppressed because too long, use -v for the full output>"
+			if !testingVerbose() {
+				if n := strings.Count(v, "\n"); n > longValueLines {
+					v = fmt.Sprintf("<suppressed due to length (%d lines), use -v for full output>", n)
+				}
 			}
 		} else {
 			v = p.format(value)