diff --git a/src/StringManipulation.c b/src/StringManipulation.c
index 2863f93..6f671da 100644
--- a/src/StringManipulation.c
+++ b/src/StringManipulation.c
@@ -4,7 +4,10 @@ char *to_string(int number)
 {
 	if(number==0)
 	{
-		return "0\0";
+		char *str = calloc(2,sizeof(char));
+		*(str) = '0';
+		*(str+1) = '\0';
+		return str;
 	}
 	else
 	{
@@ -22,3 +25,19 @@ char *to_string(int number)
 	return str;
 	}
 }
+
+char *generateCheckString(int ID, char *password)
+{
+	char *IDString = to_string(ID);
+	int IDLength = strlen(IDString);
+	int passwordLength = strlen(password);
+	/*the checkString has this form: ID=password, so in order to calculate its length the length of the ID, one byte for the =, the length of the password and
+	 * one byte for '\0' are needed.*/
+	int checkStringLength = IDLength + 1 + passwordLength + 1;
+	char *checkString = calloc(checkStringLength, sizeof(char));
+	checkString = strcat(IDString, "=");
+	checkString = strcat(checkString, password);
+	*(checkString+checkStringLength) = '\0';
+	return checkString;:w
+
+}
diff --git a/src/StringManipulation.h b/src/StringManipulation.h
index 88f06a4..d1a8b35 100644
--- a/src/StringManipulation.h
+++ b/src/StringManipulation.h
@@ -1,3 +1,5 @@
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 char *to_string(int);
+char *generateCheckString(int, char *);
diff --git a/tests/build/test/cache/defines_dependency.yml b/tests/build/test/cache/defines_dependency.yml
new file mode 100644
index 0000000..551c1ff
--- /dev/null
+++ b/tests/build/test/cache/defines_dependency.yml
@@ -0,0 +1,3 @@
+---
+"/home/julius/Documents/Studium/Informatik/1. Semester/ProgMeth/Bankmanagement/bankmanagement-system/src/StringManipulation.c":
+- TEST
diff --git a/tests/build/test/cache/input.yml b/tests/build/test/cache/input.yml
new file mode 100644
index 0000000..fb9e794
--- /dev/null
+++ b/tests/build/test/cache/input.yml
@@ -0,0 +1,242 @@
+---
+:project:
+  :use_exceptions: false
+  :use_mocks: true
+  :compile_threads: 1
+  :test_threads: 1
+  :use_test_preprocessor: true
+  :use_preprocessor_directives: false
+  :use_deep_dependencies: false
+  :generate_deep_dependencies: true
+  :auto_link_deep_dependencies: false
+  :test_file_prefix: test_
+  :options_paths: []
+  :release_build: false
+  :use_auxiliary_dependencies: true
+  :build_root: build
+  :which_ceedling: gem
+  :ceedling_version: 0.31.1
+  :default_tasks:
+  - test:all
+:release_build:
+  :use_assembly: false
+  :artifacts: []
+:paths:
+  :test:
+  - "+:test/**"
+  - "-:test/support"
+  :source:
+  - "/home/julius/Documents/Studium/Informatik/1. Semester/ProgMeth/Bankmanagement/bankmanagement-system/src/**"
+  :support:
+  - test/support
+  :include: []
+  :libraries: []
+  :test_toolchain_include: []
+  :release_toolchain_include: []
+:files:
+  :test: []
+  :source: []
+  :assembly: []
+  :support: []
+  :include: []
+:environment:
+- :rake_columns: '120'
+:defines:
+  :test:
+  - &1 []
+  - TEST
+  :test_preprocess:
+  - *1
+  - TEST
+  :release: []
+  :release_preprocess: []
+  :use_test_definition: false
+  :common: []
+:libraries:
+  :flag: "-l${1}"
+  :path_flag: "-L ${1}"
+  :test: []
+  :test_preprocess: []
+  :release: []
+  :release_preprocess: []
+  :placement: :end
+  :system: []
+:flags: {}
+:extension:
+  :header: ".h"
+  :source: ".c"
+  :assembly: ".s"
+  :object: ".o"
+  :libraries:
+  - ".a"
+  - ".so"
+  :executable: ".out"
+  :map: ".map"
+  :list: ".lst"
+  :testpass: ".pass"
+  :testfail: ".fail"
+  :dependencies: ".d"
+:unity:
+  :vendor_path: "/var/lib/gems/2.7.0/gems/ceedling-0.31.1/vendor"
+  :defines: []
+:cmock:
+  :vendor_path: "/var/lib/gems/2.7.0/gems/ceedling-0.31.1/vendor"
+  :defines: []
+  :includes: []
+  :mock_prefix: mock_
+  :when_no_prototypes: :warn
+  :enforce_strict_ordering: true
+  :plugins:
+  - :ignore
+  - :callback
+  :treat_as:
+    uint8: HEX8
+    uint16: HEX16
+    uint32: UINT32
+    int8: INT8
+    bool: UINT8
+  :mock_path: build/test/mocks
+  :verbosity: 3
+  :unity_helper: false
+:cexception:
+  :vendor_path: "/var/lib/gems/2.7.0/gems/ceedling-0.31.1/vendor"
+  :defines: []
+:test_runner:
+  :includes: []
+  :file_suffix: _runner
+:tools:
+  :test_compiler:
+    :executable: gcc
+    :name: default_test_compiler
+    :stderr_redirect: :none
+    :background_exec: :none
+    :optional: false
+    :arguments:
+    - ''
+    - ''
+    - -I"$": COLLECTION_PATHS_TEST_SUPPORT_SOURCE_INCLUDE_VENDOR
+    - -I"$": COLLECTION_PATHS_TEST_TOOLCHAIN_INCLUDE
+    - "-D$": COLLECTION_DEFINES_TEST_AND_VENDOR
+    - "-DGNU_COMPILER"
+    - "-g"
+    - ''
+    - -c "${1}"
+    - -o "${2}"
+    - "-MMD"
+    - -MF "${4}"
+  :test_fixture:
+    :executable: "${1}"
+    :name: default_test_fixture
+    :stderr_redirect: :auto
+    :background_exec: :none
+    :optional: false
+    :arguments: []
+  :test_linker:
+    :executable: gcc
+    :name: default_test_linker
+    :stderr_redirect: :none
+    :background_exec: :none
+    :optional: false
+    :arguments:
+    - ''
+    - ''
+    - ''
+    - '"${1}"'
+    - "${5}"
+    - -o "${2}"
+    - ''
+    - "${4}"
+    - ''
+  :test_file_preprocessor:
+    :executable: gcc
+    :name: default_test_file_preprocessor
+    :stderr_redirect: :none
+    :background_exec: :none
+    :optional: false
+    :arguments:
+    - ''
+    - ''
+    - "-E"
+    - -I"$": COLLECTION_PATHS_TEST_SUPPORT_SOURCE_INCLUDE_VENDOR
+    - -I"$": COLLECTION_PATHS_TEST_TOOLCHAIN_INCLUDE
+    - "-D$": COLLECTION_DEFINES_TEST_AND_VENDOR
+    - "-D$": DEFINES_TEST_PREPROCESS
+    - "-DGNU_COMPILER"
+    - '"${1}"'
+    - -o "${2}"
+  :test_file_preprocessor_directives:
+    :executable: gcc
+    :name: default_test_file_preprocessor_directives
+    :stderr_redirect: :none
+    :background_exec: :none
+    :optional: false
+    :arguments:
+    - "-E"
+    - -I"$": COLLECTION_PATHS_TEST_SUPPORT_SOURCE_INCLUDE_VENDOR
+    - -I"$": COLLECTION_PATHS_TEST_TOOLCHAIN_INCLUDE
+    - "-D$": COLLECTION_DEFINES_TEST_AND_VENDOR
+    - "-D$": DEFINES_TEST_PREPROCESS
+    - "-DGNU_COMPILER"
+    - "-fdirectives-only"
+    - '"${1}"'
+    - -o "${2}"
+  :test_includes_preprocessor:
+    :executable: gcc
+    :name: default_test_includes_preprocessor
+    :stderr_redirect: :none
+    :background_exec: :none
+    :optional: false
+    :arguments:
+    - ''
+    - ''
+    - "-E"
+    - "-MM"
+    - "-MG"
+    - -I"$": COLLECTION_PATHS_TEST_SUPPORT_SOURCE_INCLUDE_VENDOR
+    - -I"$": COLLECTION_PATHS_TEST_TOOLCHAIN_INCLUDE
+    - "-D$": COLLECTION_DEFINES_TEST_AND_VENDOR
+    - "-D$": DEFINES_TEST_PREPROCESS
+    - "-DGNU_COMPILER"
+    - '"${1}"'
+:test_compiler:
+  :arguments: []
+:test_linker:
+  :arguments: []
+:test_fixture:
+  :arguments: []
+  :link_objects: []
+:test_includes_preprocessor:
+  :arguments: []
+:test_file_preprocessor:
+  :arguments: []
+:test_file_preprocessor_directives:
+  :arguments: []
+:test_dependencies_generator:
+  :arguments: []
+:release_compiler:
+  :arguments: []
+:release_linker:
+  :arguments: []
+:release_assembler:
+  :arguments: []
+:release_dependencies_generator:
+  :arguments: []
+:plugins:
+  :load_paths:
+  - "/var/lib/gems/2.7.0/gems/ceedling-0.31.1/lib/../plugins"
+  :enabled:
+  - stdout_pretty_tests_report
+  - module_generator
+  :display_raw_test_results: false
+  :stdout_pretty_tests_report_path: "/var/lib/gems/2.7.0/gems/ceedling-0.31.1/lib/../plugins/stdout_pretty_tests_report"
+  :module_generator_path: "/var/lib/gems/2.7.0/gems/ceedling-0.31.1/lib/../plugins/module_generator"
+:gcov:
+  :reports:
+  - HtmlDetailed
+  :gcovr:
+    :html_medium_threshold: 75
+    :html_high_threshold: 90
+:module_generator:
+  :project_root: "./"
+  :source_root: src/
+  :test_root: test/
diff --git a/tests/build/test/cache/test_StringManipulation.c b/tests/build/test/cache/test_StringManipulation.c
new file mode 100644
index 0000000..0d87c99
--- /dev/null
+++ b/tests/build/test/cache/test_StringManipulation.c
@@ -0,0 +1,195 @@
+#include "Semester/ProgMeth/Bankmanagement/bankmanagement-system/src/StringManipulation.h"
+#include "/var/lib/gems/2.7.0/gems/ceedling-0.31.1/vendor/unity/src/unity.h"
+
+
+
+
+
+
+void test_to_string()
+
+{
+
+
+
+ char *result_1[] = {"0","1","2","3","4","5","6","7","8","9","10"};
+
+ char *result_2[] = {"500","502","504","506","508","510","512","514","516","518"};
+
+ char *result_3[] = {"1000","2000","3000","4000","5000","6000","7000","8000","9000","10000"};
+
+ char *result_4[] = {"9999","8999","7999","6999","5999","4999","3999","2999","1999","999"};
+
+ char *result_5[] = {"1000000","2000000","3000000","4000000","5000000","6000000","7000000",
+
+       "8000000","9000000","10000000"};
+
+
+
+ for(int i=0;i<=10;++i){
+
+  UnityAssertEqualString((const char*)((result_1[i])), (const char*)((to_string(i))), (
+
+ ((void *)0)
+
+ ), (UNITY_UINT)(17));
+
+ }
+
+
+
+ for(int i=0, j=500;i<10;++i,j+=2){
+
+  UnityAssertEqualString((const char*)((result_2[i])), (const char*)((to_string(j))), (
+
+ ((void *)0)
+
+ ), (UNITY_UINT)(21));
+
+ }
+
+
+
+ for(int i=0, j=1000;i<10;++i,j+=1000){
+
+  UnityAssertEqualString((const char*)((result_3[i])), (const char*)((to_string(j))), (
+
+ ((void *)0)
+
+ ), (UNITY_UINT)(25));
+
+ }
+
+
+
+ for(int i=0, j=9999;i<10;++i,j-=1000){
+
+  UnityAssertEqualString((const char*)((result_4[i])), (const char*)((to_string(j))), (
+
+ ((void *)0)
+
+ ), (UNITY_UINT)(29));
+
+ }
+
+ for(int i=0, j=1000000;i<10;++i,j+=1000000){
+
+  UnityAssertEqualString((const char*)((result_5[i])), (const char*)((to_string(j))), (
+
+ ((void *)0)
+
+ ), (UNITY_UINT)(32));
+
+ }
+
+
+
+}
+
+
+
+
+
+void test_generateCheckString()
+
+{
+
+
+
+ int numbers_1[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25};
+
+ char *strings_1[] = {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};
+
+ char *result_1[] = {"0=a","1=b","2=c","3=d","4=e","5=f","6=g","7=h","8=i","9=j","10=k","11=l","12=m","13=n","14=o","15=p","16=q","17=r", "18=s","19=t","20=u","21=v","22=w","23=x","24=y","25=z"};
+
+ for(int i=0;i<26;++i){
+
+  UnityAssertEqualString((const char*)((result_1[i])), (const char*)((generateCheckString(numbers_1[i],*(strings_1+i)))), (
+
+ ((void *)0)
+
+ ), (UNITY_UINT)(45));
+
+ }
+
+
+
+ int numbers_2[] = {0,1,1,2,3,5,8,13,21,34,55,89,144,233,377,610,987,1597,2584,4181,6765,10946,17711,28657,46368,75025};
+
+ char *strings_2[] = {"z","zy","zyx","zyxw","zyxwv","zyxwvu","zyxwvut","zyxwvuts","zyxwvutsr","zyxwvutsrq","zyxwvutsrqp",
+
+        "zyxwvutsrqpo","zyxwvutsrqpon","zyxwvutsrqponm","zyxwvutsrqponml","zyxwvutsrqponmlk",
+
+        "zyxwvutsrqponmlkj","zyxwvutsrqponmlkji","zyxwvutsrqponmlkjih","zyxwvutsrqponmlkjihg","zyxwvutsrqponmlkjihgf",
+
+         "zyxwvutsrqponmlkjihgfe","zyxwvutsrqponmlkjihgfed","zyxwvutsrqponmlkjihgfedc","zyxwvutsrqponmlkjihgfedcb",
+
+         "zyxwvutsrqponmlkjihgfedcba"};
+
+ char *result_2[] = {"0=z","1=zy","1=zyx","2=zyxw","3=zyxwv","5=zyxwvu","8=zyxwvut","13=zyxwvuts","21=zyxwvutsr","34=zyxwvutsrq",
+
+                     "55=zyxwvutsrqp","89=zyxwvutsrqpo","144=zyxwvutsrqpon","233=zyxwvutsrqponm","377=zyxwvutsrqponml",
+
+       "610=zyxwvutsrqponmlk","987=zyxwvutsrqponmlkj","1597=zyxwvutsrqponmlkji","2584=zyxwvutsrqponmlkjih",
+
+       "4181=zyxwvutsrqponmlkjihg","6765=zyxwvutsrqponmlkjihgf","10946=zyxwvutsrqponmlkjihgfe",
+
+       "17711=zyxwvutsrqponmlkjihgfed","28657=zyxwvutsrqponmlkjihgfedc","46368=zyxwvutsrqponmlkjihgfedcb",
+
+       "75025=zyxwvutsrqponmlkjihgfedcba"};
+
+ for(int i=0;i<26;++i){
+
+  UnityAssertEqualString((const char*)((result_2[i])), (const char*)((generateCheckString(numbers_2[i],*(strings_2+i)))), (
+
+ ((void *)0)
+
+ ), (UNITY_UINT)(61));
+
+ }
+
+
+
+ srand(time(0));
+
+ int random_number=0;
+
+ char *random_numbers_strings[20];
+
+ int random_numbers[20];
+
+ for(int i=0;i<20;++i){
+
+  random_number = (rand() % 100) + 1;
+
+  random_numbers_strings[i] = to_string(random_number);
+
+  random_numbers[i] = random_number;
+
+ }
+
+ char *strings_3[] = {"tree","plant","tea","programming","assembler","unix","BSD","snow","mountain","table","wood","forest", "calculator","book","light","keyboard","old","paper","pencil","voltage"};
+
+ char *result_3[20];
+
+ for(int i=0;i<20;++i){
+
+  random_numbers_strings[i] = strcat(random_numbers_strings[i],"=");
+
+  result_3[i] = strcat(random_numbers_strings[i],strings_3[i]);
+
+  printf("%s\n",result_3[i]);
+
+ }
+
+ for(int i=0;i<20;++i){
+
+  UnityAssertEqualString((const char*)((result_3[i])), (const char*)((generateCheckString(random_numbers[i],strings_3[i]))), (
+
+ ((void *)0)
+
+ ), (UNITY_UINT)(81));
+
+ }
+
+}
diff --git a/tests/build/test/dependencies/StringManipulation.d b/tests/build/test/dependencies/StringManipulation.d
new file mode 100644
index 0000000..625c690
--- /dev/null
+++ b/tests/build/test/dependencies/StringManipulation.d
@@ -0,0 +1,3 @@
+build/test/out/c/StringManipulation.o: \
+ /home/julius/Documents/Studium/Informatik/1.\ Semester/ProgMeth/Bankmanagement/bankmanagement-system/src/StringManipulation.c \
+ /home/julius/Documents/Studium/Informatik/1.\ Semester/ProgMeth/Bankmanagement/bankmanagement-system/src/StringManipulation.h
diff --git a/tests/build/test/dependencies/cmock.d b/tests/build/test/dependencies/cmock.d
new file mode 100644
index 0000000..82b64c9
--- /dev/null
+++ b/tests/build/test/dependencies/cmock.d
@@ -0,0 +1,6 @@
+build/test/out/c/cmock.o: \
+ /var/lib/gems/2.7.0/gems/ceedling-0.31.1/vendor/cmock/src/cmock.c \
+ /var/lib/gems/2.7.0/gems/ceedling-0.31.1/vendor/cmock/src/cmock.h \
+ /var/lib/gems/2.7.0/gems/ceedling-0.31.1/vendor/cmock/src/cmock_internals.h \
+ /var/lib/gems/2.7.0/gems/ceedling-0.31.1/vendor/unity/src/unity.h \
+ /var/lib/gems/2.7.0/gems/ceedling-0.31.1/vendor/unity/src/unity_internals.h
diff --git a/tests/build/test/dependencies/test_StringManipulation.d b/tests/build/test/dependencies/test_StringManipulation.d
new file mode 100644
index 0000000..2f65b3c
--- /dev/null
+++ b/tests/build/test/dependencies/test_StringManipulation.d
@@ -0,0 +1,5 @@
+build/test/out/c/test_StringManipulation.o: \
+ test/test_StringManipulation.c \
+ /var/lib/gems/2.7.0/gems/ceedling-0.31.1/vendor/unity/src/unity.h \
+ /var/lib/gems/2.7.0/gems/ceedling-0.31.1/vendor/unity/src/unity_internals.h \
+ /home/julius/Documents/Studium/Informatik/1.\ Semester/ProgMeth/Bankmanagement/bankmanagement-system/src/StringManipulation.h
diff --git a/tests/build/test/dependencies/test_StringManipulation_runner.d b/tests/build/test/dependencies/test_StringManipulation_runner.d
new file mode 100644
index 0000000..c54fbb6
--- /dev/null
+++ b/tests/build/test/dependencies/test_StringManipulation_runner.d
@@ -0,0 +1,4 @@
+build/test/out/c/test_StringManipulation_runner.o: \
+ build/test/runners/test_StringManipulation_runner.c \
+ /var/lib/gems/2.7.0/gems/ceedling-0.31.1/vendor/unity/src/unity.h \
+ /var/lib/gems/2.7.0/gems/ceedling-0.31.1/vendor/unity/src/unity_internals.h
diff --git a/tests/build/test/dependencies/unity.d b/tests/build/test/dependencies/unity.d
new file mode 100644
index 0000000..02f2997
--- /dev/null
+++ b/tests/build/test/dependencies/unity.d
@@ -0,0 +1,4 @@
+build/test/out/c/unity.o: \
+ /var/lib/gems/2.7.0/gems/ceedling-0.31.1/vendor/unity/src/unity.c \
+ /var/lib/gems/2.7.0/gems/ceedling-0.31.1/vendor/unity/src/unity.h \
+ /var/lib/gems/2.7.0/gems/ceedling-0.31.1/vendor/unity/src/unity_internals.h
diff --git a/tests/build/test/out/c/StringManipulation.o b/tests/build/test/out/c/StringManipulation.o
new file mode 100644
index 0000000..531a498
Binary files /dev/null and b/tests/build/test/out/c/StringManipulation.o differ
diff --git a/tests/build/test/out/c/cmock.o b/tests/build/test/out/c/cmock.o
new file mode 100644
index 0000000..162be59
Binary files /dev/null and b/tests/build/test/out/c/cmock.o differ
diff --git a/tests/build/test/out/c/test_StringManipulation.o b/tests/build/test/out/c/test_StringManipulation.o
new file mode 100644
index 0000000..4e6507a
Binary files /dev/null and b/tests/build/test/out/c/test_StringManipulation.o differ
diff --git a/tests/build/test/out/c/test_StringManipulation_runner.o b/tests/build/test/out/c/test_StringManipulation_runner.o
new file mode 100644
index 0000000..a16f5ca
Binary files /dev/null and b/tests/build/test/out/c/test_StringManipulation_runner.o differ
diff --git a/tests/build/test/out/c/unity.o b/tests/build/test/out/c/unity.o
new file mode 100644
index 0000000..ba42096
Binary files /dev/null and b/tests/build/test/out/c/unity.o differ
diff --git a/tests/build/test/out/test_StringManipulation.out b/tests/build/test/out/test_StringManipulation.out
new file mode 100755
index 0000000..e8425d0
Binary files /dev/null and b/tests/build/test/out/test_StringManipulation.out differ
diff --git a/tests/build/test/preprocess/files/test_StringManipulation.c b/tests/build/test/preprocess/files/test_StringManipulation.c
new file mode 100644
index 0000000..0d87c99
--- /dev/null
+++ b/tests/build/test/preprocess/files/test_StringManipulation.c
@@ -0,0 +1,195 @@
+#include "Semester/ProgMeth/Bankmanagement/bankmanagement-system/src/StringManipulation.h"
+#include "/var/lib/gems/2.7.0/gems/ceedling-0.31.1/vendor/unity/src/unity.h"
+
+
+
+
+
+
+void test_to_string()
+
+{
+
+
+
+ char *result_1[] = {"0","1","2","3","4","5","6","7","8","9","10"};
+
+ char *result_2[] = {"500","502","504","506","508","510","512","514","516","518"};
+
+ char *result_3[] = {"1000","2000","3000","4000","5000","6000","7000","8000","9000","10000"};
+
+ char *result_4[] = {"9999","8999","7999","6999","5999","4999","3999","2999","1999","999"};
+
+ char *result_5[] = {"1000000","2000000","3000000","4000000","5000000","6000000","7000000",
+
+       "8000000","9000000","10000000"};
+
+
+
+ for(int i=0;i<=10;++i){
+
+  UnityAssertEqualString((const char*)((result_1[i])), (const char*)((to_string(i))), (
+
+ ((void *)0)
+
+ ), (UNITY_UINT)(17));
+
+ }
+
+
+
+ for(int i=0, j=500;i<10;++i,j+=2){
+
+  UnityAssertEqualString((const char*)((result_2[i])), (const char*)((to_string(j))), (
+
+ ((void *)0)
+
+ ), (UNITY_UINT)(21));
+
+ }
+
+
+
+ for(int i=0, j=1000;i<10;++i,j+=1000){
+
+  UnityAssertEqualString((const char*)((result_3[i])), (const char*)((to_string(j))), (
+
+ ((void *)0)
+
+ ), (UNITY_UINT)(25));
+
+ }
+
+
+
+ for(int i=0, j=9999;i<10;++i,j-=1000){
+
+  UnityAssertEqualString((const char*)((result_4[i])), (const char*)((to_string(j))), (
+
+ ((void *)0)
+
+ ), (UNITY_UINT)(29));
+
+ }
+
+ for(int i=0, j=1000000;i<10;++i,j+=1000000){
+
+  UnityAssertEqualString((const char*)((result_5[i])), (const char*)((to_string(j))), (
+
+ ((void *)0)
+
+ ), (UNITY_UINT)(32));
+
+ }
+
+
+
+}
+
+
+
+
+
+void test_generateCheckString()
+
+{
+
+
+
+ int numbers_1[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25};
+
+ char *strings_1[] = {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};
+
+ char *result_1[] = {"0=a","1=b","2=c","3=d","4=e","5=f","6=g","7=h","8=i","9=j","10=k","11=l","12=m","13=n","14=o","15=p","16=q","17=r", "18=s","19=t","20=u","21=v","22=w","23=x","24=y","25=z"};
+
+ for(int i=0;i<26;++i){
+
+  UnityAssertEqualString((const char*)((result_1[i])), (const char*)((generateCheckString(numbers_1[i],*(strings_1+i)))), (
+
+ ((void *)0)
+
+ ), (UNITY_UINT)(45));
+
+ }
+
+
+
+ int numbers_2[] = {0,1,1,2,3,5,8,13,21,34,55,89,144,233,377,610,987,1597,2584,4181,6765,10946,17711,28657,46368,75025};
+
+ char *strings_2[] = {"z","zy","zyx","zyxw","zyxwv","zyxwvu","zyxwvut","zyxwvuts","zyxwvutsr","zyxwvutsrq","zyxwvutsrqp",
+
+        "zyxwvutsrqpo","zyxwvutsrqpon","zyxwvutsrqponm","zyxwvutsrqponml","zyxwvutsrqponmlk",
+
+        "zyxwvutsrqponmlkj","zyxwvutsrqponmlkji","zyxwvutsrqponmlkjih","zyxwvutsrqponmlkjihg","zyxwvutsrqponmlkjihgf",
+
+         "zyxwvutsrqponmlkjihgfe","zyxwvutsrqponmlkjihgfed","zyxwvutsrqponmlkjihgfedc","zyxwvutsrqponmlkjihgfedcb",
+
+         "zyxwvutsrqponmlkjihgfedcba"};
+
+ char *result_2[] = {"0=z","1=zy","1=zyx","2=zyxw","3=zyxwv","5=zyxwvu","8=zyxwvut","13=zyxwvuts","21=zyxwvutsr","34=zyxwvutsrq",
+
+                     "55=zyxwvutsrqp","89=zyxwvutsrqpo","144=zyxwvutsrqpon","233=zyxwvutsrqponm","377=zyxwvutsrqponml",
+
+       "610=zyxwvutsrqponmlk","987=zyxwvutsrqponmlkj","1597=zyxwvutsrqponmlkji","2584=zyxwvutsrqponmlkjih",
+
+       "4181=zyxwvutsrqponmlkjihg","6765=zyxwvutsrqponmlkjihgf","10946=zyxwvutsrqponmlkjihgfe",
+
+       "17711=zyxwvutsrqponmlkjihgfed","28657=zyxwvutsrqponmlkjihgfedc","46368=zyxwvutsrqponmlkjihgfedcb",
+
+       "75025=zyxwvutsrqponmlkjihgfedcba"};
+
+ for(int i=0;i<26;++i){
+
+  UnityAssertEqualString((const char*)((result_2[i])), (const char*)((generateCheckString(numbers_2[i],*(strings_2+i)))), (
+
+ ((void *)0)
+
+ ), (UNITY_UINT)(61));
+
+ }
+
+
+
+ srand(time(0));
+
+ int random_number=0;
+
+ char *random_numbers_strings[20];
+
+ int random_numbers[20];
+
+ for(int i=0;i<20;++i){
+
+  random_number = (rand() % 100) + 1;
+
+  random_numbers_strings[i] = to_string(random_number);
+
+  random_numbers[i] = random_number;
+
+ }
+
+ char *strings_3[] = {"tree","plant","tea","programming","assembler","unix","BSD","snow","mountain","table","wood","forest", "calculator","book","light","keyboard","old","paper","pencil","voltage"};
+
+ char *result_3[20];
+
+ for(int i=0;i<20;++i){
+
+  random_numbers_strings[i] = strcat(random_numbers_strings[i],"=");
+
+  result_3[i] = strcat(random_numbers_strings[i],strings_3[i]);
+
+  printf("%s\n",result_3[i]);
+
+ }
+
+ for(int i=0;i<20;++i){
+
+  UnityAssertEqualString((const char*)((result_3[i])), (const char*)((generateCheckString(random_numbers[i],strings_3[i]))), (
+
+ ((void *)0)
+
+ ), (UNITY_UINT)(81));
+
+ }
+
+}
diff --git a/tests/build/test/preprocess/includes/test_StringManipulation.c b/tests/build/test/preprocess/includes/test_StringManipulation.c
new file mode 100644
index 0000000..77ded96
--- /dev/null
+++ b/tests/build/test/preprocess/includes/test_StringManipulation.c
@@ -0,0 +1,3 @@
+---
+- "/var/lib/gems/2.7.0/gems/ceedling-0.31.1/vendor/unity/src/unity.h"
+- Semester/ProgMeth/Bankmanagement/bankmanagement-system/src/StringManipulation.h
diff --git a/tests/build/test/results/test_StringManipulation.pass b/tests/build/test/results/test_StringManipulation.pass
new file mode 100644
index 0000000..84a7b10
--- /dev/null
+++ b/tests/build/test/results/test_StringManipulation.pass
@@ -0,0 +1,42 @@
+---
+:source:
+  :path: test
+  :file: test_StringManipulation.c
+:successes:
+- :test: test_to_string
+  :line: 6
+  :message: ''
+  :unity_test_time: 0
+- :test: test_generateCheckString
+  :line: 38
+  :message: ''
+  :unity_test_time: 0
+:failures: []
+:ignores: []
+:counts:
+  :total: 2
+  :passed: 2
+  :failed: 0
+  :ignored: 0
+:stdout:
+- 9=tree
+- 26=plant
+- 92=tea
+- 31=programming
+- 75=assembler
+- 28=unix
+- 92=BSD
+- 99=snow
+- 10=mountain
+- 43=table
+- 92=wood
+- 98=forest
+- 3=calculator
+- 32=book
+- 29=light
+- 92=keyboard
+- 35=old
+- 27=paper
+- 85=pencil
+- 91=voltage
+:time: 0.0019293400000606198
diff --git a/tests/build/test/runners/test_StringManipulation_runner.c b/tests/build/test/runners/test_StringManipulation_runner.c
new file mode 100644
index 0000000..8c93227
--- /dev/null
+++ b/tests/build/test/runners/test_StringManipulation_runner.c
@@ -0,0 +1,89 @@
+/* AUTOGENERATED FILE. DO NOT EDIT. */
+
+/*=======Automagically Detected Files To Include=====*/
+#include "unity.h"
+
+int GlobalExpectCount;
+int GlobalVerifyOrder;
+char* GlobalOrderError;
+
+/*=======External Functions This Runner Calls=====*/
+extern void setUp(void);
+extern void tearDown(void);
+extern void test_to_string();
+extern void test_generateCheckString();
+
+
+/*=======Mock Management=====*/
+static void CMock_Init(void)
+{
+  GlobalExpectCount = 0;
+  GlobalVerifyOrder = 0;
+  GlobalOrderError = NULL;
+}
+static void CMock_Verify(void)
+{
+}
+static void CMock_Destroy(void)
+{
+}
+
+/*=======Setup (stub)=====*/
+void setUp(void) {}
+
+/*=======Teardown (stub)=====*/
+void tearDown(void) {}
+
+/*=======Test Reset Options=====*/
+void resetTest(void);
+void resetTest(void)
+{
+  tearDown();
+  CMock_Verify();
+  CMock_Destroy();
+  CMock_Init();
+  setUp();
+}
+void verifyTest(void);
+void verifyTest(void)
+{
+  CMock_Verify();
+}
+
+/*=======Test Runner Used To Run Each Test=====*/
+static void run_test(UnityTestFunction func, const char* name, UNITY_LINE_TYPE line_num)
+{
+    Unity.CurrentTestName = name;
+    Unity.CurrentTestLineNumber = line_num;
+#ifdef UNITY_USE_COMMAND_LINE_ARGS
+    if (!UnityTestMatches())
+        return;
+#endif
+    Unity.NumberOfTests++;
+    UNITY_CLR_DETAILS();
+    UNITY_EXEC_TIME_START();
+    CMock_Init();
+    if (TEST_PROTECT())
+    {
+        setUp();
+        func();
+    }
+    if (TEST_PROTECT())
+    {
+        tearDown();
+        CMock_Verify();
+    }
+    CMock_Destroy();
+    UNITY_EXEC_TIME_STOP();
+    UnityConcludeTest();
+}
+
+/*=======MAIN=====*/
+int main(void)
+{
+  UnityBegin("test_StringManipulation.c");
+  run_test(test_to_string, "test_to_string", 6);
+  run_test(test_generateCheckString, "test_generateCheckString", 38);
+
+  return UnityEnd();
+}
diff --git a/tests/project.yml b/tests/project.yml
new file mode 100644
index 0000000..7245e5e
--- /dev/null
+++ b/tests/project.yml
@@ -0,0 +1,101 @@
+---
+
+# Notes:
+# Sample project C code is not presently written to produce a release artifact.
+# As such, release build options are disabled.
+# This sample, therefore, only demonstrates running a collection of unit tests.
+
+:project:
+  :use_exceptions: FALSE
+  :use_test_preprocessor: TRUE
+  :use_auxiliary_dependencies: TRUE
+  :build_root: build
+#  :release_build: TRUE
+  :test_file_prefix: test_
+  :which_ceedling: gem
+  :ceedling_version: 0.31.1
+  :default_tasks:
+    - test:all
+
+#:test_build:
+#  :use_assembly: TRUE
+
+#:release_build:
+#  :output: MyApp.out
+#  :use_assembly: FALSE
+
+:environment:
+
+:extension:
+  :executable: .out
+
+:paths:
+  :test:
+    - +:test/**
+    - -:test/support
+  :source:
+    - /home/julius/Documents/Studium/Informatik/1. Semester/ProgMeth/Bankmanagement/bankmanagement-system/src/**
+  :support:
+    - test/support
+  :libraries: []
+
+:defines:
+  # in order to add common defines:
+  #  1) remove the trailing [] from the :common: section
+  #  2) add entries to the :common: section (e.g. :test: has TEST defined)
+  :common: &common_defines []
+  :test:
+    - *common_defines
+    - TEST
+  :test_preprocess:
+    - *common_defines
+    - TEST
+
+:cmock:
+  :mock_prefix: mock_
+  :when_no_prototypes: :warn
+  :enforce_strict_ordering: TRUE
+  :plugins:
+    - :ignore
+    - :callback
+  :treat_as:
+    uint8:    HEX8
+    uint16:   HEX16
+    uint32:   UINT32
+    int8:     INT8
+    bool:     UINT8
+
+# Add -gcov to the plugins list to make sure of the gcov plugin
+# You will need to have gcov and gcovr both installed to make it work.
+# For more information on these options, see docs in plugins/gcov
+:gcov:
+  :reports:
+    - HtmlDetailed
+  :gcovr:
+    :html_medium_threshold: 75
+    :html_high_threshold: 90
+
+#:tools:
+# Ceedling defaults to using gcc for compiling, linking, etc.
+# As [:tools] is blank, gcc will be used (so long as it's in your system path)
+# See documentation to configure a given toolchain for use
+
+# LIBRARIES
+# These libraries are automatically injected into the build process. Those specified as
+# common will be used in all types of builds. Otherwise, libraries can be injected in just
+# tests or releases. These options are MERGED with the options in supplemental yaml files.
+:libraries:
+  :placement: :end
+  :flag: "-l${1}"
+  :path_flag: "-L ${1}"
+  :system: []    # for example, you might list 'm' to grab the math library
+  :test: []
+  :release: []
+
+:plugins:
+  :load_paths:
+    - "#{Ceedling.load_path}"
+  :enabled:
+    - stdout_pretty_tests_report
+    - module_generator
+...
diff --git a/tests/test_StringManipulation.c b/tests/test_StringManipulation.c
index b8ca872..accd414 100644
--- a/tests/test_StringManipulation.c
+++ b/tests/test_StringManipulation.c
@@ -1,5 +1,7 @@
 #include "unity.h"
 #include "StringManipulation.h"
+#include <time.h>
+#include <string.h>
 
 void test_to_string() 
 {
@@ -12,27 +14,70 @@ void test_to_string()
 			    "8000000","9000000","10000000"};
 
 	for(int i=0;i<=10;++i){
-		printf("%s\n", to_string(i));
 		TEST_ASSERT_EQUAL_STRING(result_1[i],to_string(i));
 	}	
 	
 	for(int i=0, j=500;i<10;++i,j+=2){
-		printf("%s\n", to_string(j));
 		TEST_ASSERT_EQUAL_STRING(result_2[i],to_string(j));
 	}
 
 	for(int i=0, j=1000;i<10;++i,j+=1000){
-		printf("%s\n", to_string(j));
 		TEST_ASSERT_EQUAL_STRING(result_3[i],to_string(j));	
 	}
 	
 	for(int i=0, j=9999;i<10;++i,j-=1000){
-		printf("%s\n", to_string(j));
 		TEST_ASSERT_EQUAL_STRING(result_4[i], to_string(j));
 	}
 	for(int i=0, j=1000000;i<10;++i,j+=1000000){
-		printf("%s\n", to_string(j));
 		TEST_ASSERT_EQUAL_STRING(result_5[i],to_string(j));
 	}
 
 }
+
+
+void test_generateCheckString() 
+{
+	/*test block 1*/
+	int numbers_1[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25};
+	char *strings_1[] = {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};
+	char *result_1[] = {"0=a","1=b","2=c","3=d","4=e","5=f","6=g","7=h","8=i","9=j","10=k","11=l","12=m","13=n","14=o","15=p","16=q","17=r",                            "18=s","19=t","20=u","21=v","22=w","23=x","24=y","25=z"};
+	for(int i=0;i<26;++i){
+		TEST_ASSERT_EQUAL_STRING(result_1[i],generateCheckString(numbers_1[i],*(strings_1+i)));
+	}
+	/*test block 2*/
+	int numbers_2[] = {0,1,1,2,3,5,8,13,21,34,55,89,144,233,377,610,987,1597,2584,4181,6765,10946,17711,28657,46368,75025};
+	char *strings_2[] = {"z","zy","zyx","zyxw","zyxwv","zyxwvu","zyxwvut","zyxwvuts","zyxwvutsr","zyxwvutsrq","zyxwvutsrqp",
+			     "zyxwvutsrqpo","zyxwvutsrqpon","zyxwvutsrqponm","zyxwvutsrqponml","zyxwvutsrqponmlk",
+			     "zyxwvutsrqponmlkj","zyxwvutsrqponmlkji","zyxwvutsrqponmlkjih","zyxwvutsrqponmlkjihg","zyxwvutsrqponmlkjihgf",
+			      "zyxwvutsrqponmlkjihgfe","zyxwvutsrqponmlkjihgfed","zyxwvutsrqponmlkjihgfedc","zyxwvutsrqponmlkjihgfedcb",
+			      "zyxwvutsrqponmlkjihgfedcba"};
+	char *result_2[] = {"0=z","1=zy","1=zyx","2=zyxw","3=zyxwv","5=zyxwvu","8=zyxwvut","13=zyxwvuts","21=zyxwvutsr","34=zyxwvutsrq",
+	                    "55=zyxwvutsrqp","89=zyxwvutsrqpo","144=zyxwvutsrqpon","233=zyxwvutsrqponm","377=zyxwvutsrqponml",
+			    "610=zyxwvutsrqponmlk","987=zyxwvutsrqponmlkj","1597=zyxwvutsrqponmlkji","2584=zyxwvutsrqponmlkjih",
+			    "4181=zyxwvutsrqponmlkjihg","6765=zyxwvutsrqponmlkjihgf","10946=zyxwvutsrqponmlkjihgfe",
+			    "17711=zyxwvutsrqponmlkjihgfed","28657=zyxwvutsrqponmlkjihgfedc","46368=zyxwvutsrqponmlkjihgfedcb",
+			    "75025=zyxwvutsrqponmlkjihgfedcba"};
+	for(int i=0;i<26;++i){
+		TEST_ASSERT_EQUAL_STRING(result_2[i],generateCheckString(numbers_2[i],*(strings_2+i)));	
+	}
+	/*test block 3*/
+	srand(time(0));
+	int random_number=0;
+	char *random_numbers_strings[20];
+	int random_numbers[20];
+	for(int i=0;i<20;++i){
+		random_number = (rand() % 100) + 1;
+		random_numbers_strings[i] = to_string(random_number);
+		random_numbers[i] = random_number;
+	}
+	char *strings_3[] = {"tree","plant","tea","programming","assembler","unix","BSD","snow","mountain","table","wood","forest", "calculator","book","light","keyboard","old","paper","pencil","voltage"};
+	char *result_3[20];
+	for(int i=0;i<20;++i){
+		random_numbers_strings[i] = strcat(random_numbers_strings[i],"=");
+		result_3[i] = strcat(random_numbers_strings[i],strings_3[i]);
+		printf("%s\n",result_3[i]);
+	}
+	for(int i=0;i<20;++i){
+		TEST_ASSERT_EQUAL_STRING(result_3[i],generateCheckString(random_numbers[i],strings_3[i]));
+	}
+}