diff --git a/cpp/ql/test/library-tests/dataflow/dataflow-tests/TestBase.qll b/cpp/ql/test/library-tests/dataflow/dataflow-tests/TestBase.qll
index b9213a71549..e28d19133c7 100644
--- a/cpp/ql/test/library-tests/dataflow/dataflow-tests/TestBase.qll
+++ b/cpp/ql/test/library-tests/dataflow/dataflow-tests/TestBase.qll
@@ -124,7 +124,11 @@ module IRTest {
 
   /** Common data flow configuration to be used by tests. */
   module IRTestAllocationConfig implements DataFlow::ConfigSig {
+    private import semmle.code.cpp.security.FlowSources
+
     predicate isSource(DataFlow::Node source) {
+      source instanceof FlowSource
+      or
       source.asExpr().(FunctionCall).getTarget().getName() = "source"
       or
       source.asIndirectExpr(1).(FunctionCall).getTarget().getName() = "indirect_source"
diff --git a/cpp/ql/test/library-tests/dataflow/dataflow-tests/winmain.cpp b/cpp/ql/test/library-tests/dataflow/dataflow-tests/winmain.cpp
new file mode 100644
index 00000000000..3db41088842
--- /dev/null
+++ b/cpp/ql/test/library-tests/dataflow/dataflow-tests/winmain.cpp
@@ -0,0 +1,9 @@
+void sink(char);
+void sink(char*);
+
+int WinMain(void *hInstance, void *hPrevInstance, char *pCmdLine, int nCmdShow) { // $ ast-def=hInstance ast-def=hPrevInstance ast-def=pCmdLine ir-def=*hInstance ir-def=*hPrevInstance ir-def=*pCmdLine 
+  sink(pCmdLine);
+  sink(*pCmdLine); // $ MISSING: ir
+
+  return 0;
+}
diff --git a/cpp/ql/test/library-tests/dataflow/external-models/windows.cpp b/cpp/ql/test/library-tests/dataflow/external-models/windows.cpp
new file mode 100644
index 00000000000..33f496be0f0
--- /dev/null
+++ b/cpp/ql/test/library-tests/dataflow/external-models/windows.cpp
@@ -0,0 +1,31 @@
+void sink(char);
+void sink(char*);
+void sink(char**);
+
+char* GetCommandLineA();
+char** CommandLineToArgvA(char*, int*);
+char* GetEnvironmentStringsA();
+int GetEnvironmentVariableA(const char*, char*, int);
+
+void getCommandLine() {
+  char* cmd = GetCommandLineA();
+  sink(cmd);
+  sink(*cmd); // $ MISSING: ir
+
+  int argc;
+  char** argv = CommandLineToArgvA(cmd, &argc);
+  sink(argv);
+  sink(argv[1]);
+  sink(*argv[1]); // $ MISSING: ir
+}
+
+void getEnvironment() {
+    char* env = GetEnvironmentStringsA();
+    sink(env);
+    sink(*env); // $ MISSING: ir
+
+    char buf[1024];
+    GetEnvironmentVariableA("FOO", buf, sizeof(buf));
+    sink(buf);
+    sink(*buf); // $ MISSING: ir
+}