diff --git a/P02_QR_Code_auf_Terminal/bit-manipulation/tests/tests.c b/P02_QR_Code_auf_Terminal/bit-manipulation/tests/tests.c
old mode 100755
new mode 100644
diff --git a/P02_QR_Code_auf_Terminal/qr-code/tests/tests.c b/P02_QR_Code_auf_Terminal/qr-code/tests/tests.c
old mode 100755
new mode 100644
diff --git a/P03_Bounding_Box/bounding-box/tests/tests.c b/P03_Bounding_Box/bounding-box/tests/tests.c
old mode 100755
new mode 100644
diff --git a/P03_Bounding_Box/wochentag-berechnung/tests/tests.c b/P03_Bounding_Box/wochentag-berechnung/tests/tests.c
old mode 100755
new mode 100644
diff --git a/P04_Modularisieren_von_C_Code/show-dependencies/tests/tests.c b/P04_Modularisieren_von_C_Code/show-dependencies/tests/tests.c
old mode 100755
new mode 100644