diff --git a/lib/crypto/sha256/sha256_test.ww b/lib/crypto/sha256/sha256_test.ww
index d734ccea..4e593ffc 100644
--- a/lib/crypto/sha256/sha256_test.ww
+++ b/lib/crypto/sha256/sha256_test.ww
@@ -8,7 +8,7 @@
 // the rest of the 9xx stdlib tests; the non-zero exit pinpoints the
 // failing case. Expected digests come through the (separately tested)
 // hex.decodestr so the vectors stay readable.
-package sha256;
+package sha256_test;
 
 import bytes;
 import crypto.sha256;
diff --git a/lib/encoding/utf8/utf8test.ww b/lib/encoding/utf8/utf8test.ww
index 62f6b711..46b07243 100644
--- a/lib/encoding/utf8/utf8test.ww
+++ b/lib/encoding/utf8/utf8test.ww
@@ -3,7 +3,7 @@
 // then-fail()-with-+10 pattern as hex / base32 / time tests:
 // non-zero exit pinpoints the failing scenario.
 
-package utf8;
+package utf8_test;
 
 import bytes;
 import encoding.utf8;
diff --git a/lib/math/checked/checked_test.ww b/lib/math/checked/checked_test.ww
index af7836fe..9f96fa67 100644
--- a/lib/math/checked/checked_test.ww
+++ b/lib/math/checked/checked_test.ww
@@ -1,4 +1,4 @@
-package checked;
+package checked_test;
 
 // Directory import pulls both checked.ww and saturating.ww (the two
 // files of this module); a bare `import checked` would resolve only to