Added FloatBetween validation function.

helper/validation/validation.go

@@ -266,3 +266,22 @@ func ValidateRFC3339TimeString(v interface{}, k string) (ws []string, errors []e
 	}
 	return
 }
+
+// FloatBetween returns a SchemaValidateFunc which tests if the provided value
+// is of type float64 and is between min and max (inclusive).
+func FloatBetween(min, max float64) schema.SchemaValidateFunc {
+	return func(i interface{}, k string) (s []string, es []error) {
+		v, ok := i.(float64)
+		if !ok {
+			es = append(es, fmt.Errorf("expected type of %s to be float64", k))
+			return
+		}
+
+		if v < min || v > max {
+			es = append(es, fmt.Errorf("expected %s to be in the range (%f - %f), got %f", k, min, max, v))
+			return
+		}
+
+		return
+	}
+}

helper/validation/validation_test.go

@@ -373,3 +373,46 @@ func runTestCases(t *testing.T, cases []testCase) {
 		}
 	}
 }
+
+func TestFloatBetween(t *testing.T) {
+	cases := map[string]struct {
+		Value                  interface{}
+		ValidateFunc           schema.SchemaValidateFunc
+		ExpectValidationErrors bool
+	}{
+		"accept valid value": {
+			Value:                  1.5,
+			ValidateFunc:           FloatBetween(1.0, 2.0),
+			ExpectValidationErrors: false,
+		},
+		"accept valid value inclusive upper bound": {
+			Value:                  1.0,
+			ValidateFunc:           FloatBetween(0.0, 1.0),
+			ExpectValidationErrors: false,
+		},
+		"accept valid value inclusive lower bound": {
+			Value:                  0.0,
+			ValidateFunc:           FloatBetween(0.0, 1.0),
+			ExpectValidationErrors: false,
+		},
+		"reject out of range value": {
+			Value:                  -1.0,
+			ValidateFunc:           FloatBetween(0.0, 1.0),
+			ExpectValidationErrors: true,
+		},
+		"reject incorrectly typed value": {
+			Value:                  1,
+			ValidateFunc:           FloatBetween(0.0, 1.0),
+			ExpectValidationErrors: true,
+		},
+	}
+
+	for tn, tc := range cases {
+		_, errors := tc.ValidateFunc(tc.Value, tn)
+		if len(errors) > 0 && !tc.ExpectValidationErrors {
+			t.Errorf("%s: unexpected errors %s", tn, errors)
+		} else if len(errors) == 0 && tc.ExpectValidationErrors {
+			t.Errorf("%s: expected errors but got none", tn)
+		}
+	}
+}