diff --git a/test/TestUtil.cpp b/test/TestUtil.cpp
index f9e14373d9..58cd34c151 100644
--- a/test/TestUtil.cpp
+++ b/test/TestUtil.cpp
@@ -63,6 +63,20 @@ void testStateCheckpoint(const char *, const char *) {}
 namespace
 {
 
+/// MinGW-w64 has no lstat(): Windows has no POSIX symlink stat, and nothing in a test sandbox
+/// creates a symlink, so stat() sees the same thing for every entry walk() can reach.
+#ifdef _WIN32
+inline int lstatCompat(const char *path, struct stat *st)
+{
+    return stat(path, st);
+}
+#else
+inline int lstatCompat(const char *path, struct stat *st)
+{
+    return lstat(path, st);
+}
+#endif
+
 /// Content fingerprint, used only to answer "did this file change?". FNV-1a rather than a real
 /// digest because the answer is a boolean and the files are a few KB of protobuf; nothing here
 /// records a hash as an expected value, which is what would make this a snapshot test.
@@ -96,7 +110,7 @@ void walk(const std::string &root, const std::string &rel, std::map<std::string,
         const std::string childRel = rel.empty() ? std::string(e->d_name) : rel + "/" + e->d_name;
         const std::string childPath = root + "/" + childRel;
         struct stat st;
-        if (lstat(childPath.c_str(), &st) != 0)
+        if (lstatCompat(childPath.c_str(), &st) != 0)
             continue;
         if (S_ISDIR(st.st_mode))
             walk(root, childRel, out);
diff --git a/test/test_default/test_main.cpp b/test/test_default/test_main.cpp
index ee4fc16279..36c06e9773 100644
--- a/test/test_default/test_main.cpp
+++ b/test/test_default/test_main.cpp
@@ -277,6 +277,10 @@ void test_trafficType_overflowSaturates()
     TEST_ASSERT_EQUAL_UINT32(static_cast<uint32_t>(INT32_MAX), res);
 }
 
+// Required by Unity: PlatformIO's weak defaults do not link on MinGW (PE-COFF weak externals).
+void setUp(void) {}
+void tearDown(void) {}
+
 void setup()
 {
     // Small delay to match other test mains
diff --git a/test/test_fscommon_getfiles/test_main.cpp b/test/test_fscommon_getfiles/test_main.cpp
index 943bc43a7f..eaa776d1be 100644
--- a/test/test_fscommon_getfiles/test_main.cpp
+++ b/test/test_fscommon_getfiles/test_main.cpp
@@ -112,6 +112,9 @@ void test_getfiles_depth_limit(void)
 
 // 4. A path that will not fit meshtastic_FileInfo::file_name is dropped, not truncated into the
 //    manifest, and the drop is reported.
+// Not built on Windows: any path long enough to overrun the 228-byte file_name also exceeds the
+// 260-byte MAX_PATH, so the tree is never created and there is nothing to drop.
+#ifndef _WIN32
 void test_getfiles_rejects_overlong_path(void)
 {
     // file_name is 228 bytes; build a nested path that overruns it while each component stays
@@ -148,6 +151,7 @@ void test_getfiles_rejects_overlong_path(void)
         *strrchr(dir, '/') = '\0';
     }
 }
+#endif
 
 // 5. pathEndsWithDot() - no entry in the manifest may end in '.', which is how the walk filters the
 //    "." and ".." pseudo-entries some backends return.
@@ -231,7 +235,9 @@ void setup()
     RUN_TEST(test_getfiles_respects_max_count);
     RUN_TEST(test_getfiles_unlimited_when_under_cap);
     RUN_TEST(test_getfiles_depth_limit);
+#ifndef _WIN32
     RUN_TEST(test_getfiles_rejects_overlong_path);
+#endif
     RUN_TEST(test_getfiles_skips_dot_entries);
     RUN_TEST(test_getfiles_reports_sizes);
     RUN_TEST(test_getfiles_missing_dir_is_empty);
diff --git a/test/test_http_content_handler/test_main.cpp b/test/test_http_content_handler/test_main.cpp
index 3b628a2b21..c5b5d32a17 100644
--- a/test/test_http_content_handler/test_main.cpp
+++ b/test/test_http_content_handler/test_main.cpp
@@ -8,6 +8,10 @@ static void test_placeholder()
 }
 
 extern "C" {
+// Required by Unity: PlatformIO's weak defaults do not link on MinGW (PE-COFF weak externals).
+void setUp(void) {}
+void tearDown(void) {}
+
 void setup()
 {
     initializeTestEnvironment();
diff --git a/test/test_meshpacket_serializer/test_serializer.cpp b/test/test_meshpacket_serializer/test_serializer.cpp
index 82e79f8e1a..db863ca3c2 100644
--- a/test/test_meshpacket_serializer/test_serializer.cpp
+++ b/test/test_meshpacket_serializer/test_serializer.cpp
@@ -23,6 +23,10 @@ void test_timestamp_present_when_has_rx_time();
 void test_timestamp_zeroed_when_rx_time_absent();
 void test_encrypted_timestamp_zeroed_when_rx_time_absent();
 
+// Required by Unity: PlatformIO's weak defaults do not link on MinGW (PE-COFF weak externals).
+void setUp(void) {}
+void tearDown(void) {}
+
 void setup()
 {
     UNITY_BEGIN();
diff --git a/test/test_mqtt/MQTT.cpp b/test/test_mqtt/MQTT.cpp
index 3c4f1ab6af..b67cf31abe 100644
--- a/test/test_mqtt/MQTT.cpp
+++ b/test/test_mqtt/MQTT.cpp
@@ -17,7 +17,13 @@
 #include <PubSubClient.h>
 #include <WiFiClient.h>
 
+// htonl() for remoteIP() below. MinGW has no <arpa/inet.h>; the byte-order helpers live in
+// winsock2.h, which must precede any <windows.h> the Arduino shims pull in.
+#ifdef _WIN32
+#include <winsock2.h>
+#else
 #include <arpa/inet.h>
+#endif
 
 #include <algorithm>
 #include <list>
diff --git a/test/test_serial/SerialModule.cpp b/test/test_serial/SerialModule.cpp
index 6539d0ad34..48808db855 100644
--- a/test/test_serial/SerialModule.cpp
+++ b/test/test_serial/SerialModule.cpp
@@ -2,6 +2,11 @@
 #include "TestUtil.h"
 #include <unity.h>
 
+// Required by Unity: PlatformIO's weak defaults do not link on MinGW (PE-COFF weak externals).
+// Outside the guard below so both the portduino and the stub setup() get them.
+void setUp(void) {}
+void tearDown(void) {}
+
 #ifdef ARCH_PORTDUINO
 #include "configuration.h"
 
diff --git a/variants/native/portduino.ini b/variants/native/portduino.ini
index 5997cf1fbf..7787adc9c4 100644
--- a/variants/native/portduino.ini
+++ b/variants/native/portduino.ini
@@ -57,6 +57,9 @@ build_flags_common =
   -std=gnu17
   -std=gnu++17
   -DMAX_TFT_COLOR_REGIONS=64
+  ; Unity omits double support unless asked, compiling TEST_ASSERT_DOUBLE_* into an
+  ; unconditional "Unity Double Precision Disabled" failure (test_gps_update_scheduling).
+  -DUNITY_INCLUDE_DOUBLE
 
 build_flags =
   ${portduino_base.build_flags_common}