diff --git a/tests/regression/issue_524/SConscript b/tests/regression/issue_524/SConscript
new file mode 100644
index 0000000..d3885bc
--- /dev/null
+++ b/tests/regression/issue_524/SConscript
@@ -0,0 +1,11 @@
+# Regression test for #524:
+# Generator fails to find dependencies from another package namespace
+
+Import('env')
+
+env.NanopbProto("submessage.proto")
+env.NanopbProto("oneof.proto")
+env.Depends("oneof.pb.c", "submessage.proto")
+env.Object("oneof.pb.c")
+env.Match(["oneof.pb.h", "oneof.expected"])
+
diff --git a/tests/regression/issue_524/oneof.expected b/tests/regression/issue_524/oneof.expected
new file mode 100644
index 0000000..2f33f68
--- /dev/null
+++ b/tests/regression/issue_524/oneof.expected
@@ -0,0 +1 @@
+mymessage_MyMessage_size.*[0-9]*$
diff --git a/tests/regression/issue_524/oneof.proto b/tests/regression/issue_524/oneof.proto
new file mode 100644
index 0000000..4bdee37
--- /dev/null
+++ b/tests/regression/issue_524/oneof.proto
@@ -0,0 +1,15 @@
+syntax = "proto3";
+
+import "submessage.proto";
+
+package mymessage;
+
+message MyMessage
+{
+    oneof foo
+    {
+        submessage.SubMessage1 msg1 = 1;
+        submessage.SubMessage2 msg2 = 2;
+        submessage.SubMessage3 msg3 = 3;
+    }
+}
diff --git a/tests/regression/issue_524/submessage.proto b/tests/regression/issue_524/submessage.proto
new file mode 100644
index 0000000..ec6f7da
--- /dev/null
+++ b/tests/regression/issue_524/submessage.proto
@@ -0,0 +1,19 @@
+syntax = "proto3";
+
+package submessage;
+
+message SubMessage1
+{
+    uint32 foo = 1;
+}
+
+message SubMessage2
+{
+    uint32 foo = 1;
+}
+
+message SubMessage3
+{
+    uint32 foo = 1;
+    uint32 bar = 2;
+}