fix bug when comparing empty lines

.metadata/version

@@ -1 +1 @@
-2.0.13
+2.0.14

cmp/empty.go

@@ -13,9 +13,13 @@ func (Empty) ShortDisplay(int) string {
 }
 
 func (Empty) compare(
-	Comparable,
-	bool,
-	big.Decimal,
+	c Comparable,
+	_ bool,
+	_ big.Decimal,
 ) ([]verdictRange, big.Decimal) {
-	return []verdictRange{{Value: Verdicts.Correct}}, big.Decimal{}
+	if _, ok := c.(Empty); ok {
+		return []verdictRange{{Value: Verdicts.Correct}}, big.Decimal{}
+	}
+
+	return []verdictRange{{Value: Verdicts.Incorrect}}, big.Decimal{}
 }

integration/data/7/ans

@@ -0,0 +1,3 @@
+1
+2
+3

integration/data/7/in

@@ -0,0 +1 @@
+1

integration/verdicts_test.go

@@ -19,6 +19,13 @@ func TestWrongAnswer(t *testing.T) {
 	expectEq(t, lines[len(lines)-1], res)
 }
 
+func TestEmptyWrongAnswer(t *testing.T) {
+	lines := getLines(7)
+	res := "\033[31;1mWrong Answer\033[0;22m\033[31;1;22m 1/3\033[0;22;0m"
+
+	expectEq(t, lines[len(lines)-1], res)
+}
+
 func TestApprox(t *testing.T) {
 	lines := getLines(3)
 	res := "\033[32;1mAccepted\033[0;22m\033[32;1;22m 1/1\033[0;22;0m"