From 74585ae5f54b45964d75f16d465fdce5d0e563aa Mon Sep 17 00:00:00 2001
From: Ken Brownfield <61438713+nashikb@users.noreply.github.com>
Date: Sun, 24 Jan 2021 18:53:14 -0800
Subject: [PATCH] feat: Add ability to ignore interface{} population with
 SetIgnoreInterface() (#123)

* feat: Add ability to ignore interface{} population with SetIgnoreInterface()

* Update mod

* Revert "Update mod"

This reverts commit e78f28e83b12586e08ddc3f7664c6d83cd10943a.

* feat: update random integer boundary handling to accept a 0-span range of numbers. Good for reliable testing of 0 values.
---
 faker.go      | 18 ++++++++++++++++--
 faker_test.go | 13 +++++++++++++
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/faker.go b/faker.go
index d10ccd5..d97bd3a 100644
--- a/faker.go
+++ b/faker.go
@@ -30,6 +30,8 @@ var (
 	randomSize = 100
 	// Sets the single fake data generator to generate unique values
 	generateUniqueValues = false
+	// Sets whether interface{}s should be ignored.
+	ignoreInterface = false
 	// Unique values are kept in memory so the generator retries if the value already exists
 	uniqueValues = map[string][]interface{}{}
 	// Lang is selected language for random string generator
@@ -278,6 +280,11 @@ func SetGenerateUniqueValues(unique bool) {
 	generateUniqueValues = unique
 }
 
+// SetIgnoreInterface allows to set a flag to ignore found interface{}s.
+func SetIgnoreInterface(ignore bool) {
+	ignoreInterface = ignore
+}
+
 // SetNilIfLenIsZero allows to set nil for the slice and maps, if size is 0.
 func SetNilIfLenIsZero(setNil bool) {
 	shouldSetNil = setNil
@@ -407,6 +414,9 @@ func RemoveProvider(tag string) error {
 func getValue(a interface{}) (reflect.Value, error) {
 	t := reflect.TypeOf(a)
 	if t == nil {
+		if ignoreInterface {
+			return reflect.New(reflect.TypeOf(reflect.Struct)), nil
+		}
 		return reflect.Value{}, fmt.Errorf("interface{} not allowed")
 	}
 	k := t.Kind()
@@ -1098,12 +1108,16 @@ func randomString(n int, lang *langRuneBoundary) (string, error) {
 
 // randomIntegerWithBoundary returns a random integer between input start and end boundary. [start, end)
 func randomIntegerWithBoundary(boundary numberBoundary) int {
-	return rand.Intn(boundary.end-boundary.start) + boundary.start
+	span := boundary.end - boundary.start
+	if span <= 0 {
+		return boundary.start
+	}
+	return rand.Intn(span) + boundary.start
 }
 
 // randomInteger returns a random integer between start and end boundary. [start, end)
 func randomInteger() int {
-	return rand.Intn(nBoundary.end-nBoundary.start) + nBoundary.start
+	return randomIntegerWithBoundary(nBoundary)
 }
 
 // randomSliceAndMapSize returns a random integer between [0,randomSliceAndMapSize). If the testRandZero is set, returns 0
diff --git a/faker_test.go b/faker_test.go
index e8dce13..7fff340 100644
--- a/faker_test.go
+++ b/faker_test.go
@@ -482,6 +482,19 @@ func TestSetNilIfLenIsZero(t *testing.T) {
 	testRandZero = false
 }
 
+func TestSetIgnoreInterface(t *testing.T) {
+	SetIgnoreInterface(false)
+	var someInterface interface{}
+	if err := FakeData(&someInterface); err == nil {
+		t.Error("Fake data generation didn't fail on interface{}")
+	}
+	SetIgnoreInterface(true)
+	if err := FakeData(&someInterface); err != nil {
+		t.Error("Fake data generation fail on interface{} with SetIgnoreInterface(true)")
+	}
+	SetIgnoreInterface(false)
+}
+
 func TestBoundaryAndLen(t *testing.T) {
 	iterate := 10
 	someStruct := SomeStructWithLen{}