Unit tests around command behavior across connections

Relates to npgsql#395

Npgsql/NpgsqlCommand.cs

@@ -309,6 +309,26 @@ public Int64 LastInsertedOID
             get { return _lastInsertedOid; }
         }
 
+        /// <summary>
+        /// Returns whether this query will execute as a prepared (compiled) query.
+        /// </summary>
+        public bool IsPrepared
+        {
+            get
+            {
+                switch (_prepared)
+                {
+                    case PrepareStatus.NotPrepared:
+                        return false;
+                    case PrepareStatus.NeedsPrepare:
+                    case PrepareStatus.Prepared:
+                        return true;
+                    default:
+                        throw new ArgumentOutOfRangeException();
+                }
+            }
+        }
+
         #endregion Public properties
 
         #region State management

tests/CommandTests.cs

@@ -4175,5 +4175,73 @@ public void DisposePreparedAfterCommandClose()
                 }
             }
         }
+
+        [Test]
+        [IssueLink("https://github.com/npgsql/npgsql/issues/395")]
+        public void PreparedAcrossCloseOpen()
+        {
+            using (var c = new NpgsqlConnection(ConnectionString))
+            {
+                using (var cmd = c.CreateCommand())
+                {
+                    c.Open();
+                    cmd.CommandText = "SELECT 1";
+                    cmd.Prepare();
+                    Assert.That(cmd.IsPrepared, Is.True);
+                    c.Close();
+                    c.Open();
+                    Assert.That(cmd.IsPrepared, Is.False);
+                    cmd.Prepare();
+                    Assert.That(cmd.ExecuteScalar(), Is.EqualTo(1));
+                }
+            }
+        }
+
+        [Test]
+        [IssueLink("https://github.com/npgsql/npgsql/issues/395")]
+        public void UseAcrossConnectionChange([Values(PrepareOrNot.Prepared, PrepareOrNot.NotPrepared)] PrepareOrNot prepare)
+        {
+            using (var c = new NpgsqlConnection(ConnectionString))
+            {
+                using (var cmd = c.CreateCommand())
+                {
+                    c.Open();
+                    cmd.CommandText = "SELECT 1";
+                    if (prepare == PrepareOrNot.Prepared)
+                        cmd.Prepare();
+                    cmd.Connection = Conn;
+                    Assert.That(cmd.IsPrepared, Is.False);
+                    if (prepare == PrepareOrNot.Prepared)
+                        cmd.Prepare();
+                    Assert.That(cmd.ExecuteScalar(), Is.EqualTo(1));
+                }
+            }
+        }
+
+        [Test]
+        [IssueLink("https://github.com/npgsql/npgsql/issues/395")]
+        public void DefaultCommandTimeout()
+        {
+            if (Conn.Connector.DefaultCommandTimeout >= 100 && Conn.Connector.DefaultCommandTimeout < 105)
+                TestUtil.Inconclusive("Bad default command timeout");
+            using (var c1 = new NpgsqlConnection(ConnectionString + ";CommandTimeout=100"))
+            {
+                using (var cmd = c1.CreateCommand())
+                {
+                    Assert.That(cmd.CommandTimeout, Is.EqualTo(100));
+                    using (var c2 = new NpgsqlConnection(ConnectionString + ";CommandTimeout=101"))
+                    {
+                        cmd.Connection = c2;
+                        Assert.That(cmd.CommandTimeout, Is.EqualTo(101));
+                    }
+                    cmd.CommandTimeout = 102;
+                    using (var c2 = new NpgsqlConnection(ConnectionString + ";CommandTimeout=101"))
+                    {
+                        cmd.Connection = c2;
+                        Assert.That(cmd.CommandTimeout, Is.EqualTo(102));
+                    }
+                }
+            }
+        }
     }
 }