diff --git a/lib/check64bit.h b/lib/check64bit.h
index bafb5646aaa..eaa99787646 100644
--- a/lib/check64bit.h
+++ b/lib/check64bit.h
@@ -41,8 +41,6 @@ class Tokenizer;
  */
 
 class CPPCHECKLIB Check64BitPortability : public Check {
-    friend class Test64BitPortability;
-
 public:
     /** This constructor is used when registering the Check64BitPortability */
     Check64BitPortability() : Check("64-bit portability") {}
diff --git a/lib/checkclass.h b/lib/checkclass.h
index ccf154b645d..2bc47194bee 100644
--- a/lib/checkclass.h
+++ b/lib/checkclass.h
@@ -49,10 +49,6 @@ enum class FunctionType : std::uint8_t;
 
 /** @brief %Check classes. Uninitialized member variables, non-conforming operators, missing virtual destructor, etc */
 class CPPCHECKLIB CheckClass : public Check {
-    friend class TestClass;
-    friend class TestConstructors;
-    friend class TestUnusedPrivateFunction;
-
 public:
     /** @brief This constructor is used when registering the CheckClass */
     CheckClass() : Check("Class") {}
diff --git a/lib/checkio.h b/lib/checkio.h
index e881e22cbf3..8efaa4833c1 100644
--- a/lib/checkio.h
+++ b/lib/checkio.h
@@ -42,8 +42,6 @@ enum class Severity : std::uint8_t;
 
 /** @brief %Check input output operations. */
 class CPPCHECKLIB CheckIO : public Check {
-    friend class TestIO;
-
 public:
     /** @brief This constructor is used when registering CheckIO */
     CheckIO() : Check("IO using format string") {}
diff --git a/lib/checkmemoryleak.h b/lib/checkmemoryleak.h
index 4fa69742277..32d5750389c 100644
--- a/lib/checkmemoryleak.h
+++ b/lib/checkmemoryleak.h
@@ -65,8 +65,6 @@ enum class Severity : std::uint8_t;
  */
 
 class CPPCHECKLIB CheckMemoryLeakInFunction : public Check {
-    friend class TestMemleakInFunction;
-
 public:
     /** @brief This constructor is used when registering this class */
     CheckMemoryLeakInFunction() : Check("Memory leaks (function variables)") {}
@@ -92,8 +90,6 @@ class CPPCHECKLIB CheckMemoryLeakInFunction : public Check {
  */
 
 class CPPCHECKLIB CheckMemoryLeakInClass : public Check {
-    friend class TestMemleakInClass;
-
 public:
     CheckMemoryLeakInClass() : Check("Memory leaks (class variables)") {}
 
@@ -112,8 +108,6 @@ class CPPCHECKLIB CheckMemoryLeakInClass : public Check {
 /** @brief detect simple memory leaks for struct members */
 
 class CPPCHECKLIB CheckMemoryLeakStructMember : public Check {
-    friend class TestMemleakStructMember;
-
 public:
     CheckMemoryLeakStructMember() : Check("Memory leaks (struct members)") {}
 
@@ -132,8 +126,6 @@ class CPPCHECKLIB CheckMemoryLeakStructMember : public Check {
 /** @brief detect simple memory leaks (address not taken) */
 
 class CPPCHECKLIB CheckMemoryLeakNoVar : public Check {
-    friend class TestMemleakNoVar;
-
 public:
     CheckMemoryLeakNoVar() : Check("Memory leaks (address not taken)") {}
 
diff --git a/lib/checknullpointer.h b/lib/checknullpointer.h
index 8e35fd7565a..bfc59d8974e 100644
--- a/lib/checknullpointer.h
+++ b/lib/checknullpointer.h
@@ -48,8 +48,6 @@ namespace ValueFlow
 /** @brief check for null pointer dereferencing */
 
 class CPPCHECKLIB CheckNullPointer : public Check {
-    friend class TestNullPointer;
-
 public:
     /** @brief This constructor is used when registering the CheckNullPointer */
     CheckNullPointer() : Check("Null pointer") {}
diff --git a/lib/checkother.h b/lib/checkother.h
index 97291b53769..97e62d08725 100644
--- a/lib/checkother.h
+++ b/lib/checkother.h
@@ -50,10 +50,6 @@ struct UnionMember;
 /** @brief Various small checks */
 
 class CPPCHECKLIB CheckOther : public Check {
-    friend class TestCharVar;
-    friend class TestIncompleteStatement;
-    friend class TestOther;
-
 public:
     /** @brief This constructor is used when registering the CheckClass */
     CheckOther() : Check("Other") {}
diff --git a/lib/checkpostfixoperator.h b/lib/checkpostfixoperator.h
index de51a34fe42..6d285eaded8 100644
--- a/lib/checkpostfixoperator.h
+++ b/lib/checkpostfixoperator.h
@@ -41,8 +41,6 @@ class Tokenizer;
  */
 
 class CPPCHECKLIB CheckPostfixOperator : public Check {
-    friend class TestPostfixOperator;
-
 public:
     /** This constructor is used when registering the CheckPostfixOperator */
     CheckPostfixOperator() : Check("Using postfix operators") {}
diff --git a/lib/checkuninitvar.h b/lib/checkuninitvar.h
index f558fe84709..898538ac19e 100644
--- a/lib/checkuninitvar.h
+++ b/lib/checkuninitvar.h
@@ -58,8 +58,6 @@ struct VariableValue {
 /** @brief Checking for uninitialized variables */
 
 class CPPCHECKLIB CheckUninitVar : public Check {
-    friend class TestUninitVar;
-
 public:
     /** @brief This constructor is used when registering the CheckUninitVar */
     CheckUninitVar() : Check("Uninitialized variables") {}
diff --git a/lib/checkunusedvar.h b/lib/checkunusedvar.h
index cddc36bb7e3..549928e3d48 100644
--- a/lib/checkunusedvar.h
+++ b/lib/checkunusedvar.h
@@ -43,8 +43,6 @@ class Tokenizer;
 /** @brief Various small checks */
 
 class CPPCHECKLIB CheckUnusedVar : public Check {
-    friend class TestUnusedVar;
-
 public:
     /** @brief This constructor is used when registering the CheckClass */
     CheckUnusedVar() : Check("UnusedVar") {}