1 files changed, 39 insertions, 0 deletions
diff --git a/src/test/isolation/specs/read-write-unique.spec b/src/test/isolation/specs/read-write-unique.spec
new file mode 100644
index 00000000000..c782f10c43e
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+++ b/src/test/isolation/specs/read-write-unique.spec
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+# Read-write-unique test.
+
+setup
+{
+  CREATE TABLE test (i integer PRIMARY KEY);
+}
+
+teardown
+{
+  DROP TABLE test;
+}
+
+session "s1"
+setup { BEGIN ISOLATION LEVEL SERIALIZABLE; }
+step "r1" { SELECT * FROM test; }
+step "w1" { INSERT INTO test VALUES (42); }
+step "c1" { COMMIT; }
+
+session "s2"
+setup { BEGIN ISOLATION LEVEL SERIALIZABLE; }
+step "r2" { SELECT * FROM test; }
+step "w2" { INSERT INTO test VALUES (42); }
+step "c2" { COMMIT; }
+
+# Two SSI transactions see that there is no row with value 42
+# in the table, then try to insert that value; T1 inserts,
+# and then T2 blocks waiting for T1 to commit.  Finally,
+# T2 reports a serialization failure.
+#
+# (In an earlier version of Postgres, T2 would report a unique
+# constraint violation).
+
+permutation "r1" "r2" "w1" "w2" "c1" "c2"
+
+# If the value is already visible before T2 begins, then a
+# regular unique constraint violation should still be raised
+# by T2.
+
+permutation "r1" "w1" "c1" "r2" "w2" "c2"