[Xposed Framework Modules] Joy2DaWurld:
I'll do you one better and post here the root detection code from the decompiled app. There are two direct references in the latest version of the app. Here is "Root.smali":

.class public Lcom/gpshopper/adidas/objects/Root;
.super Ljava/lang/Object;
.source "Root.java"

# static fields
.field private static LOG_TAG:Ljava/lang/String;

# direct methods
.method static constructor <clinit>()V
.locals 1

.prologue
.line 11
const-class v0, Lcom/gpshopper/adidas/objects/Root;

invoke-virtual {v0}, Ljava/lang/Class;->getName()Ljava/lang/String;

move-result-object v0

sput-object v0, Lcom/gpshopper/adidas/objects/Root;->LOG_TAG:Ljava/lang/String;

return-void
.end method

.method public constructor <init>()V
.locals 0

.prologue
.line 8
invoke-direct {p0}, Ljava/lang/Object;-><init>()V

return-void
.end method

.method public static checkRootMethod1()Z
.locals 2

.prologue
.line 18
sget-object v0, Landroid/os/Build;->TAGS:Ljava/lang/String;

.line 19
.local v0, "buildTags":Ljava/lang/String;
if-eqz v0, :cond_0

const-string v1, "test-keys"

invoke-virtual {v0, v1}, Ljava/lang/String;->contains(Ljava/lang/CharSequence;)Z

move-result v1

if-eqz v1, :cond_0

const/4 v1, 0x1

:goto_0
return v1

:cond_0
const/4 v1, 0x0

goto :goto_0
.end method

.method public static checkRootMethod2()Z
.locals 5

.prologue
const/4 v3, 0x0

.line 25
:try_start_0
new-instance v1, Ljava/io/File;

const-string v4, "/system/app/Superuser.apk"

invoke-direct {v1, v4}, Ljava/io/File;-><init>(Ljava/lang/String;)V

.line 26
.local v1, "file":Ljava/io/File;
new-instance v2, Ljava/io/File;

const-string v4, "/system/app/SuperSU/SuperSU.apk"

invoke-direct {v2, v4}, Ljava/io/File;-><init>(Ljava/lang/String;)V

.line 27
.local v2, "file1":Ljava/io/File;
invoke-virtual {v1}, Ljava/io/File;->exists()Z

move-result v4

if-nez v4, :cond_0

invoke-virtual {v2}, Ljava/io/File;->exists()Z
:try_end_0
.catch Ljava/lang/Exception; {:try_start_0 .. :try_end_0} :catch_0

move-result v4

if-eqz v4, :cond_1

:cond_0
const/4 v3, 0x1

.line 29
.end local v2 # "file1":Ljava/io/File;
:cond_1
:goto_0
return v3

.line 28
:catch_0
move-exception v0

.line 29
.local v0, "e":Ljava/lang/Exception;
goto :goto_0
.end method

.method public static checkRootMethod3()Z
.locals 2

.prologue
.line 36
new-instance v0, Lcom/gpshopper/adidas/objects/ExecShell;

invoke-direct {v0}, Lcom/gpshopper/adidas/objects/ExecShell;-><init>()V

sget-object v1, Lcom/gpshopper/adidas/objects/ExecShell$SHELL_CMD;->check_su_binary:Lcom/gpshopper/adidas/objects/ExecShell$SHELL_CMD;

invoke-virtual {v0, v1}, Lcom/gpshopper/adidas/objects/ExecShell;->executeCommand(Lcom/gpshopper/adidas/objects/ExecShell$SHELL_CMD;)Ljava/util/ArrayList;

move-result-object v0

if-eqz v0, :cond_0

const/4 v0, 0x1

:goto_0
return v0

:cond_0
const/4 v0, 0x0

goto :goto_0
.end method

.method public static isDeviceRooted()Z
.locals 1

.prologue
.line 14
invoke-static {}, Lcom/gpshopper/adidas/objects/Root;->checkRootMethod1()Z

move-result v0

if-nez v0, :cond_0

invoke-static {}, Lcom/gpshopper/adidas/objects/Root;->checkRootMethod2()Z

move-result v0

if-nez v0, :cond_0

invoke-static {}, Lcom/gpshopper/adidas/objects/Root;->checkRootMethod3()Z

move-result v0

if-eqz v0, :cond_1

:cond_0
const/4 v0, 0x1

:goto_0
return v0

:cond_1
const/4 v0, 0x0

goto :goto_0
.end method

And here is Root.java (this one makes more sense to me with my minimal coding experience):

// Decompiled by Jad v1.5.8e. Copyright 2001 Pavel Kouznetsov.
// Jad home page: http://www.geocities.com/kpdus/jad.html
// Decompiler options: braces fieldsfirst space lnc

package com.gpshopper.adidas.objects;

import android.os.Build;
import java.io.File;

// Referenced classes of package com.gpshopper.adidas.objects:
// ExecShell

public class Root
{

private static String LOG_TAG = com/gpshopper/adidas/objects/Root.getName();

public Root()
{
}

public static boolean checkRootMethod1()
{
String s = Build.TAGS;
return s != null && s.contains("test-keys");
}

public static boolean checkRootMethod2()
{
label0:
{
label1:
{
boolean flag = false;
boolean flag1;
try
{
File file = new File("/system/app/Superuser.apk");
File file1 = new File("/system/app/SuperSU/SuperSU.apk");
if (file.exists())
{
break label1;
}
flag1 = file1.exists();
}
catch (Exception exception)
{
return false;
}
if (!flag1)
{
break label0;
}
}
flag = true;
}
return flag;
}

public static boolean checkRootMethod3()
{
return (new ExecShell()).executeCommand(ExecShell.SHELL_CMD.check_su_binary) != null;
}

public static boolean isDeviceRooted()
{
return checkRootMethod1() || checkRootMethod2() || checkRootMethod3();
}

}

These are the two main modules within the APK referencing a "root check," however I have attached the full decompiled version for your please :)

Hopefully you smart folks will be able to get farther than I did with this...

https://drive.google.com/file/d/0B3d2t_Zy6wnhMDM3elRTR0NNWk0/view?usp=sharing