diff --git a/tests/platform/lpc804/lpc804.ino b/tests/platform/lpc804/lpc804.ino
index b44698cc..7b209beb 100644
--- a/tests/platform/lpc804/lpc804.ino
+++ b/tests/platform/lpc804/lpc804.ino
@@ -6,6 +6,8 @@
 // its own variant core (zackees/ArduinoCore-LPC8xx) provides the real
 // register-level GPIO implementation.
 
+#include <Arduino.h>
+
 #ifndef LED_BUILTIN
 #define LED_BUILTIN 0
 #endif
diff --git a/tests/platform/lpc845/lpc845.ino b/tests/platform/lpc845/lpc845.ino
index 7b1fdd1b..23e24a26 100644
--- a/tests/platform/lpc845/lpc845.ino
+++ b/tests/platform/lpc845/lpc845.ino
@@ -6,6 +6,8 @@
 // its own variant core (zackees/ArduinoCore-LPC8xx) provides the real
 // register-level GPIO implementation.
 
+#include <Arduino.h>
+
 #ifndef LED_BUILTIN
 #define LED_BUILTIN 0
 #endif
diff --git a/tests/platform/lpc845_build_flags/src/main.ino b/tests/platform/lpc845_build_flags/src/main.ino
index d39f885d..53f1edd5 100644
--- a/tests/platform/lpc845_build_flags/src/main.ino
+++ b/tests/platform/lpc845_build_flags/src/main.ino
@@ -5,6 +5,8 @@
 // nxplpc library compile path. A working build proves the orchestrator now
 // folds `ctx.user_flags` into the `LibraryBuildEnv` flag set.
 
+#include <Arduino.h>
+
 extern void check_flag_no_op();
 
 void setup() {
diff --git a/tests/platform/lpc845brk/lpc845brk.ino b/tests/platform/lpc845brk/lpc845brk.ino
index 660bdbcc..5f780864 100644
--- a/tests/platform/lpc845brk/lpc845brk.ino
+++ b/tests/platform/lpc845brk/lpc845brk.ino
@@ -1,2 +1,4 @@
+#include <Arduino.h>
+
 void setup() {}
 void loop() {}
diff --git a/tests/platform/lpcxpresso804/lpcxpresso804.ino b/tests/platform/lpcxpresso804/lpcxpresso804.ino
index 660bdbcc..5f780864 100644
--- a/tests/platform/lpcxpresso804/lpcxpresso804.ino
+++ b/tests/platform/lpcxpresso804/lpcxpresso804.ino
@@ -1,2 +1,4 @@
+#include <Arduino.h>
+
 void setup() {}
 void loop() {}
diff --git a/tests/platform/lpcxpresso845max/lpcxpresso845max.ino b/tests/platform/lpcxpresso845max/lpcxpresso845max.ino
index 660bdbcc..5f780864 100644
--- a/tests/platform/lpcxpresso845max/lpcxpresso845max.ino
+++ b/tests/platform/lpcxpresso845max/lpcxpresso845max.ino
@@ -1,2 +1,4 @@
+#include <Arduino.h>
+
 void setup() {}
 void loop() {}