Return error instead of nil when 'Find' fails

regex/matching.go

@@ -148,7 +148,7 @@ func pruneIndices(indices []Match) []Match {
 func (regex Reg) Find(str string) (Group, error) {
 	match, err := regex.FindNthMatch(str, 1)
 	if err != nil {
-		return Group{}, nil
+		return Group{}, fmt.Errorf("no matches found")
 	}
 	return getZeroGroup(match), nil
 }

regex/re_test.go

@@ -673,7 +673,33 @@ var groupTests = []struct {
 	{`(<389-400>)`, nil, `391`, []Match{[]Group{{0, 3}, {0, 3}}}},
 }
 
-func TestFindAllMatches(t *testing.T) {
+func TestFind(t *testing.T) {
+	for _, test := range reTests {
+		t.Run(test.re+"	"+test.str, func(t *testing.T) {
+			regComp, err := Compile(test.re, test.flags...)
+			if err != nil {
+				if test.result != nil {
+					panic(fmt.Errorf("Test Error: %v", err))
+				}
+			} else {
+				groupIndex, err := regComp.Find(test.str)
+				if err != nil { // No matches found
+					if len(test.result) == 0 {
+						return // Manually pass the test, because this is the expected behavior
+					} else {
+						t.Errorf("Wanted no match Got %v\n", groupIndex)
+					}
+				} else {
+					if groupIndex != test.result[0] {
+						t.Errorf("Wanted %v	Got %v\n", test.result, groupIndex)
+					}
+				}
+			}
+		})
+	}
+}
+
+func TestFindAll(t *testing.T) {
 	for _, test := range reTests {
 		t.Run(test.re+"	"+test.str, func(t *testing.T) {
 			regComp, err := Compile(test.re, test.flags...)
@@ -716,7 +742,7 @@ func TestFindString(t *testing.T) {
 	}
 }
 
-func TestFindAllStrings(t *testing.T) {
+func TestFindAllString(t *testing.T) {
 	for _, test := range reTests {
 		t.Run(test.re+"	"+test.str, func(t *testing.T) {
 			regComp, err := Compile(test.re, test.flags...)
@@ -741,7 +767,7 @@ func TestFindAllStrings(t *testing.T) {
 	}
 }
 
-func TestFindAllGroups(t *testing.T) {
+func TestFindAllSubmatch(t *testing.T) {
 	for _, test := range groupTests {
 		t.Run(test.re+"	"+test.str, func(t *testing.T) {
 			regComp, err := Compile(test.re, test.flags...)