Added Not constraint

Author: cmaglie

constraints.go

@@ -246,3 +246,21 @@ func (and *And) String() string {
 	res += ")"
 	return res
 }
+
+// Not match if Operand does not match and viceversa
+type Not struct {
+	Operand Constraint
+}
+
+// Match returns ture if v does NOT satisfies the condition
+func (not *Not) Match(v *Version) bool {
+	return !not.Operand.Match(v)
+}
+
+func (not *Not) String() string {
+	op := not.Operand.String()
+	if op[0] != '(' {
+		return "!(" + op + ")"
+	}
+	return "!" + op
+}

constraints_test.go

@@ -69,6 +69,14 @@ func TestConstraints(t *testing.T) {
 	require.False(t, or.Match(v("2.0.0")))
 	require.True(t, or.Match(v("2.1.0")))
 	require.Equal(t, "(>2.0.0 || <=1.0.0)", or.String())
+
+	notOr := &Not{or}
+	require.False(t, notOr.Match(v("0.9.0")))
+	require.False(t, notOr.Match(v("1.0.0")))
+	require.True(t, notOr.Match(v("1.3.0")))
+	require.True(t, notOr.Match(v("2.0.0")))
+	require.False(t, notOr.Match(v("2.1.0")))
+	require.Equal(t, "!(>2.0.0 || <=1.0.0)", notOr.String())
 }
 
 func TestConstraintsParser(t *testing.T) {