diff --git a/src/sv2v.hs b/src/sv2v.hs
index fb67bbc..95da2a8 100644
--- a/src/sv2v.hs
+++ b/src/sv2v.hs
@@ -30,15 +30,19 @@ isPackage :: Description -> Bool
 isPackage Package{} = True
 isPackage _ = False
 
-emptyWarnings :: [AST] -> [AST] -> IO ()
+isComment :: Description -> Bool
+isComment (PackageItem (Decl CommentDecl{})) = True
+isComment _ = False
+
+emptyWarnings :: AST -> AST -> IO ()
 emptyWarnings before after =
-    if all null before || any (not . null) after then
+    if all isComment before || not (all isComment after) then
         return ()
-    else if any (any isInterface) before then
+    else if any isInterface before then
         hPutStrLn stderr $ "Warning: Source includes an interface but output is"
             ++ " empty because there is no top-level module which has no ports"
             ++ " which are interfaces."
-    else if any (any isPackage) before then
+    else if any isPackage before then
         hPutStrLn stderr $ "Warning: Source includes packages but no modules."
             ++ " Please convert packages alongside the modules that use them."
     else
@@ -82,7 +86,7 @@ main = do
         Right asts -> do
             -- convert the files
             let asts' = convert (exclude job) asts
-            emptyWarnings asts asts'
+            emptyWarnings (concat asts) (concat asts')
             -- write the converted files out
             writeOutput (write job) (files job) asts'
             exitSuccess
diff --git a/test/warning/interface.sv b/test/warning/interface.sv
new file mode 100644
index 0000000..d20fee8
--- /dev/null
+++ b/test/warning/interface.sv
@@ -0,0 +1,3 @@
+interface Interface;
+    logic x;
+endinterface
diff --git a/test/warning/module.sv b/test/warning/module.sv
new file mode 100644
index 0000000..01e2db1
--- /dev/null
+++ b/test/warning/module.sv
@@ -0,0 +1,4 @@
+module Module;
+    Interface intf();
+    assign intf.x = Package::X;
+endmodule
diff --git a/test/warning/package.sv b/test/warning/package.sv
new file mode 100644
index 0000000..9af1789
--- /dev/null
+++ b/test/warning/package.sv
@@ -0,0 +1,3 @@
+package Package;
+    localparam X = 1;
+endpackage
diff --git a/test/warning/run.sh b/test/warning/run.sh
new file mode 100755
index 0000000..f3824ff
--- /dev/null
+++ b/test/warning/run.sh
@@ -0,0 +1,43 @@
+#!/bin/bash
+
+PACKAGE_WARNING="Warning: Source includes packages but no modules. Please convert packages alongside the modules that use them."
+INTERFACE_WARNING="Warning: Source includes an interface but output is empty because there is no top-level module which has no ports which are interfaces."
+
+test_default() {
+    runAndCapture *.sv
+    assertTrue "default conversion should succeed" $result
+    assertNotNull "stdout should not be empty" "$stdout"
+    assertNull "stderr should be empty" "$stderr"
+}
+
+test_only_package() {
+    runAndCapture package.sv
+    assertTrue "conversion should succeed" $result
+    assertNull "stdout should be empty" "$stdout"
+    assertEquals "stderr should have warning" "$PACKAGE_WARNING" "$stderr"
+}
+
+test_only_package_verbose() {
+    runAndCapture -v package.sv
+    assertTrue "conversion should succeed" $result
+    assertNotNull "stdout should not be empty" "$stdout"
+    assertEquals "stderr should have warning" "$PACKAGE_WARNING" "$stderr"
+}
+
+test_only_interface() {
+    runAndCapture interface.sv
+    assertTrue "conversion should succeed" $result
+    assertNull "stdout should be empty" "$stdout"
+    assertEquals "stderr should have warning" "$INTERFACE_WARNING" "$stderr"
+}
+
+test_only_interface_verbose() {
+    runAndCapture -v interface.sv
+    assertTrue "conversion should succeed" $result
+    assertNotNull "stdout should not be empty" "$stdout"
+    assertEquals "stderr should have warning" "$INTERFACE_WARNING" "$stderr"
+}
+
+source ../lib/functions.sh
+
+. shunit2