light cli: add feature flags and save providers (#5148)

libs/math/fraction.go

@@ -1,6 +1,11 @@
 package math
 
-import "fmt"
+import (
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+)
 
 // Fraction defined in terms of a numerator divided by a denominator in int64
 // format.
@@ -15,3 +20,23 @@ type Fraction struct {
 func (fr Fraction) String() string {
 	return fmt.Sprintf("%d/%d", fr.Numerator, fr.Denominator)
 }
+
+// ParseFractions takes the string of a fraction as input i.e "2/3" and converts this
+// to the equivalent fraction else returns an error. The format of the string must be
+// one number followed by a slash (/) and then the other number.
+func ParseFraction(f string) (Fraction, error) {
+	o := strings.SplitN(f, "/", -1)
+	if len(o) != 2 {
+		return Fraction{}, errors.New("incorrect formating: should be like \"1/3\"")
+	}
+	numerator, err := strconv.ParseInt(o[0], 10, 64)
+	if err != nil {
+		return Fraction{}, fmt.Errorf("incorrect formatting, err: %w", err)
+	}
+
+	denominator, err := strconv.ParseInt(o[1], 10, 64)
+	if err != nil {
+		return Fraction{}, fmt.Errorf("incorrect formatting, err: %w", err)
+	}
+	return Fraction{Numerator: numerator, Denominator: denominator}, nil
+}

libs/math/fraction_test.go

@@ -0,0 +1,68 @@
+package math
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestParseFraction(t *testing.T) {
+
+	testCases := []struct {
+		f   string
+		exp Fraction
+		err bool
+	}{
+		{
+			f:   "2/3",
+			exp: Fraction{2, 3},
+			err: false,
+		},
+		{
+			f:   "15/5",
+			exp: Fraction{15, 5},
+			err: false,
+		},
+		{
+			f:   "-1/2",
+			exp: Fraction{-1, 2},
+			err: false,
+		},
+		{
+			f:   "1/-2",
+			exp: Fraction{1, -2},
+			err: false,
+		},
+		{
+			f:   "2/3/4",
+			exp: Fraction{},
+			err: true,
+		},
+		{
+			f:   "123",
+			exp: Fraction{},
+			err: true,
+		},
+		{
+			f:   "1a2/4",
+			exp: Fraction{},
+			err: true,
+		},
+		{
+			f:   "1/3bc4",
+			exp: Fraction{},
+			err: true,
+		},
+	}
+
+	for idx, tc := range testCases {
+		output, err := ParseFraction(tc.f)
+		if tc.err {
+			assert.Error(t, err, idx)
+		} else {
+			assert.NoError(t, err, idx)
+		}
+		assert.Equal(t, tc.exp, output, idx)
+	}
+
+}