helper: tests

internal/helper/type_float.go

@@ -1,6 +1,16 @@
 package helper
 
-// converts a floating point percentage to a parts per million value
+import (
+	"fmt"
+)
+
+// FloatToPPM converts a floating point percentage to a parts per million value
 func FloatToPPM(f float64) int {
 	return int(f * 10000)
 }
+
+// FloatToPercentString converts a floating point percentage to a string, with a maximum of
+// 4 decimal places, no trailing zeros
+func FloatToPercentString(f float64) string {
+	return fmt.Sprintf("%g", f)
+}

internal/helper/type_float_test.go

@@ -22,8 +22,29 @@ func TestTypeFloat_FloatToPPM(t *testing.T) {
 		{input: 0.0001, expected: 1},
 	}
 	for _, testCase := range testCases {
-		t.Run(fmt.Sprintf("returns correct value for input %f", testCase.input), func(t *testing.T) {
+		t.Run(fmt.Sprintf("returns correct value for input %g", testCase.input), func(t *testing.T) {
 			assert.Equal(t, testCase.expected, FloatToPPM(testCase.input))
 		})
 	}
 }
+
+func TestTypeFloat_FloatToPercentString(t *testing.T) {
+	testCases := []struct {
+		input    float64
+		expected string
+	}{
+		{input: 100, expected: "100"},
+		{input: 99.00, expected: "99.00"},
+		{input: 9.9999, expected: "9.9999"},
+		{input: 9, expected: "9"},
+		{input: 0.1, expected: "0.1"},
+		{input: 0.01, expected: "0.01"},
+		{input: 0.001, expected: "0.001"},
+		{input: 0.0001, expected: "0.0001"},
+	}
+	for _, testCase := range testCases {
+		t.Run(fmt.Sprintf("returns correct value for input %g", testCase.input), func(t *testing.T) {
+			assert.Equal(t, testCase.expected, FloatToPercentString(testCase.input))
+		})
+	}
+}