diff --git a/src/test/compile-fail/zip-missing-check.rs b/src/test/compile-fail/zip-missing-check.rs
new file mode 100644
index 000000000000..554a670fab4d
--- /dev/null
+++ b/src/test/compile-fail/zip-missing-check.rs
@@ -0,0 +1,17 @@
+// error-pattern:Unsatisfied precondition constraint (for example, same_length
+use std;
+import std::uint;
+import std::u8;
+import std::vec::*;
+
+fn main() {
+    let a = 'a' as u8, j = 'j' as u8, k = 1u, l = 10u;
+    // Silly, but necessary
+    check u8::le(a, j);
+    check uint::le(k, l);
+    let chars = enum_chars(a, j);
+    let ints  = enum_uints(k, l);
+
+    let ps = zip(chars, ints);
+    fail "the impossible happened";
+}
\ No newline at end of file
diff --git a/src/test/run-fail/zip-different-lengths.rs b/src/test/run-fail/zip-different-lengths.rs
new file mode 100644
index 000000000000..95991e312437
--- /dev/null
+++ b/src/test/run-fail/zip-different-lengths.rs
@@ -0,0 +1,20 @@
+// In this case, the code should compile but
+// the check should fail at runtime
+// error-pattern:Predicate same_length
+use std;
+import std::uint;
+import std::u8;
+import std::vec::*;
+
+fn main() {
+    let a = 'a' as u8, j = 'j' as u8, k = 1u, l = 9u;
+    // Silly, but necessary
+    check u8::le(a, j);
+    check uint::le(k, l);
+    let chars = enum_chars(a, j);
+    let ints  = enum_uints(k, l);
+
+    check same_length(chars, ints);
+    let ps = zip(chars, ints);
+    fail "the impossible happened";
+}
\ No newline at end of file
diff --git a/src/test/run-pass/zip-same-length.rs b/src/test/run-pass/zip-same-length.rs
new file mode 100644
index 000000000000..64063fb716e3
--- /dev/null
+++ b/src/test/run-pass/zip-same-length.rs
@@ -0,0 +1,23 @@
+// In this case, the code should compile and should
+// succeed at runtime
+use std;
+import std::uint;
+
+import std::vec::*;
+
+fn main() {
+    let a = 'a' as u8, j = 'j' as u8, k = 1u, l = 10u;
+    // Silly, but necessary
+    check le_u8(a, j);
+    check uint::le(k, l);
+    let chars = enum_chars(a, j);
+    let ints  = enum_uints(k, l);
+
+/*
+    check same_length(chars, ints);
+    let ps = zip(chars, ints);
+
+    assert (head(ps) == ('a', 1u));
+    assert (last(ps) == ('j' as u8, 10u));
+*/
+}
\ No newline at end of file