diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix.h b/clang-tools-extra/test/clang-tidy/checkers/Inputs/Headers/integral_constant.h
similarity index 86%
rename from clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix.h
rename to clang-tools-extra/test/clang-tidy/checkers/Inputs/Headers/integral_constant.h
index 680321e734cc70..225bf44ca1e5b3 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix.h
+++ b/clang-tools-extra/test/clang-tidy/checkers/Inputs/Headers/integral_constant.h
@@ -1,3 +1,6 @@
+#ifndef _INTEGRAL_CONSTANT_H_
+#define _INTEGRAL_CONSTANT_H_
+
 template <class T, T v>
 struct integral_constant {
   static constexpr T value = v;
@@ -14,3 +17,5 @@ struct is_same : false_type {};
 
 template <class T>
 struct is_same<T, T> : true_type {};
+
+#endif
diff --git a/clang-tools-extra/test/clang-tidy/checkers/cert/uppercase-literal-suffix-integer.cpp b/clang-tools-extra/test/clang-tidy/checkers/cert/uppercase-literal-suffix-integer.cpp
index d6a0d56019d4fe..0dc06df4f18b4f 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/cert/uppercase-literal-suffix-integer.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/cert/uppercase-literal-suffix-integer.cpp
@@ -1,9 +1,9 @@
-// RUN: %check_clang_tidy %s cert-dcl16-c %t -- -- -I %S
+// RUN: %check_clang_tidy %s cert-dcl16-c %t -- -- -I %clang_tidy_headers
 // RUN: grep -Ev "// *[A-Z-]+:" %s > %t.cpp
-// RUN: clang-tidy %t.cpp -checks='-*,cert-dcl16-c' -fix -- -I %S
-// RUN: clang-tidy %t.cpp -checks='-*,cert-dcl16-c' -warnings-as-errors='-*,cert-dcl16-c' -- -I %S
+// RUN: clang-tidy %t.cpp -checks='-*,cert-dcl16-c' -fix -- -I %clang_tidy_headers
+// RUN: clang-tidy %t.cpp -checks='-*,cert-dcl16-c' -warnings-as-errors='-*,cert-dcl16-c' -- -I %clang_tidy_headers
 
-#include "../readability/uppercase-literal-suffix.h"
+#include "integral_constant.h"
 
 void integer_suffix() {
   static constexpr auto v0 = __LINE__; // synthetic
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-float16.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-float16.cpp
index 89c10488069e42..a790597fcff51d 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-float16.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-float16.cpp
@@ -1,6 +1,6 @@
-// RUN: %check_clang_tidy %s readability-uppercase-literal-suffix %t -- -- -target aarch64-linux-gnu -I %S
+// RUN: %check_clang_tidy %s readability-uppercase-literal-suffix %t -- -- -target aarch64-linux-gnu -I %clang_tidy_headers
 
-#include "uppercase-literal-suffix.h"
+#include "integral_constant.h"
 
 void float16_normal_literals() {
   // _Float16
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-floating-point.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-floating-point.cpp
index 27e4bd8e214414..a0dcc38c8b2311 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-floating-point.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-floating-point.cpp
@@ -1,9 +1,9 @@
-// RUN: %check_clang_tidy %s readability-uppercase-literal-suffix %t -- -- -target x86_64-pc-linux-gnu -I %S
+// RUN: %check_clang_tidy %s readability-uppercase-literal-suffix %t -- -- -target x86_64-pc-linux-gnu -I %clang_tidy_headers
 // RUN: grep -Ev "// *[A-Z-]+:" %s > %t.cpp
-// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -fix -- -target x86_64-pc-linux-gnu -I %S
-// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -warnings-as-errors='-*,readability-uppercase-literal-suffix' -- -target x86_64-pc-linux-gnu -I %S
+// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -fix -- -target x86_64-pc-linux-gnu -I %clang_tidy_headers
+// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -warnings-as-errors='-*,readability-uppercase-literal-suffix' -- -target x86_64-pc-linux-gnu -I %clang_tidy_headers
 
-#include "uppercase-literal-suffix.h"
+#include "integral_constant.h"
 
 void floating_point_suffix() {
   static constexpr auto v0 = 1.; // no literal
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-hexadecimal-floating-point.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-hexadecimal-floating-point.cpp
index 9f60abe740af7d..57d24fb5712c4f 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-hexadecimal-floating-point.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-hexadecimal-floating-point.cpp
@@ -1,9 +1,9 @@
-// RUN: %check_clang_tidy %s readability-uppercase-literal-suffix %t -- -- -target x86_64-pc-linux-gnu -I %S
+// RUN: %check_clang_tidy %s readability-uppercase-literal-suffix %t -- -- -target x86_64-pc-linux-gnu -I %clang_tidy_headers
 // RUN: grep -Ev "// *[A-Z-]+:" %s > %t.cpp
-// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -fix -- -target x86_64-pc-linux-gnu -I %S
-// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -warnings-as-errors='-*,readability-uppercase-literal-suffix' -- -target x86_64-pc-linux-gnu -I %S
+// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -fix -- -target x86_64-pc-linux-gnu -I %clang_tidy_headers
+// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -warnings-as-errors='-*,readability-uppercase-literal-suffix' -- -target x86_64-pc-linux-gnu -I %clang_tidy_headers
 
-#include "uppercase-literal-suffix.h"
+#include "integral_constant.h"
 
 void floating_point_suffix() {
   static constexpr auto v0 = 0x0p0; // no literal
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-integer-custom-list.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-integer-custom-list.cpp
index 9e83ce2c94f0d1..c787cab1fc4a75 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-integer-custom-list.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-integer-custom-list.cpp
@@ -1,9 +1,9 @@
-// RUN: %check_clang_tidy %s readability-uppercase-literal-suffix %t -- -config="{CheckOptions: [{key: readability-uppercase-literal-suffix.NewSuffixes, value: 'L;uL'}]}" -- -I %S
+// RUN: %check_clang_tidy %s readability-uppercase-literal-suffix %t -- -config="{CheckOptions: [{key: readability-uppercase-literal-suffix.NewSuffixes, value: 'L;uL'}]}" -- -I %clang_tidy_headers
 // RUN: grep -Ev "// *[A-Z-]+:" %s > %t.cpp
-// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -fix -config="{CheckOptions: [{key: readability-uppercase-literal-suffix.NewSuffixes, value: 'L;uL'}]}" -- -I %S
-// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -warnings-as-errors='-*,readability-uppercase-literal-suffix' -config="{CheckOptions: [{key: readability-uppercase-literal-suffix.NewSuffixes, value: 'L;uL'}]}" -- -I %S
+// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -fix -config="{CheckOptions: [{key: readability-uppercase-literal-suffix.NewSuffixes, value: 'L;uL'}]}" -- -I %clang_tidy_headers
+// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -warnings-as-errors='-*,readability-uppercase-literal-suffix' -config="{CheckOptions: [{key: readability-uppercase-literal-suffix.NewSuffixes, value: 'L;uL'}]}" -- -I %clang_tidy_headers
 
-#include "uppercase-literal-suffix.h"
+#include "integral_constant.h"
 
 void integer_suffix() {
   // Unsigned
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-integer-ms.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-integer-ms.cpp
index fb8dd23a536516..fe3269f2c506d3 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-integer-ms.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-integer-ms.cpp
@@ -1,9 +1,9 @@
-// RUN: %check_clang_tidy %s readability-uppercase-literal-suffix %t -- -- -target x86_64-pc-linux-gnu -I %S -fms-extensions
+// RUN: %check_clang_tidy %s readability-uppercase-literal-suffix %t -- -- -target x86_64-pc-linux-gnu -I %clang_tidy_headers -fms-extensions
 // RUN: grep -Ev "// *[A-Z-]+:" %s > %t.cpp
-// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -fix -- -target x86_64-pc-linux-gnu -I %S -fms-extensions
-// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -warnings-as-errors='-*,readability-uppercase-literal-suffix' -- -target x86_64-pc-linux-gnu -I %S -fms-extensions
+// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -fix -- -target x86_64-pc-linux-gnu -I %clang_tidy_headers -fms-extensions
+// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -warnings-as-errors='-*,readability-uppercase-literal-suffix' -- -target x86_64-pc-linux-gnu -I %clang_tidy_headers -fms-extensions
 
-#include "uppercase-literal-suffix.h"
+#include "integral_constant.h"
 
 void integer_suffix() {
   static constexpr auto v0 = __LINE__; // synthetic
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-integer.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-integer.cpp
index f4fdf29f1d73b9..c03ccc23992fc9 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-integer.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/uppercase-literal-suffix-integer.cpp
@@ -1,9 +1,9 @@
-// RUN: %check_clang_tidy %s readability-uppercase-literal-suffix %t -- -- -I %S
+// RUN: %check_clang_tidy %s readability-uppercase-literal-suffix %t -- -- -I %clang_tidy_headers
 // RUN: grep -Ev "// *[A-Z-]+:" %s > %t.cpp
-// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -fix -- -I %S
-// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -warnings-as-errors='-*,readability-uppercase-literal-suffix' -- -I %S
+// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -fix -- -I %clang_tidy_headers
+// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -warnings-as-errors='-*,readability-uppercase-literal-suffix' -- -I %clang_tidy_headers
 
-#include "uppercase-literal-suffix.h"
+#include "integral_constant.h"
 
 void integer_suffix() {
   static constexpr auto v0 = __LINE__; // synthetic