Warn that ReadUntil* must be used with 80x80 PTYs

code-asher · code-asher · commit fc281d2fec53 · 2023-08-16T11:51:37.000-08:00
diff --git a/agent/agent_test.go b/agent/agent_test.go
@@ -1630,12 +1630,12 @@ func TestAgent_ReconnectingPTY(t *testing.T) {
 			//nolint:dogsled
 			conn, _, _, _, _ := setupAgent(t, agentsdk.Manifest{}, 0)
 			id := uuid.New()
-			netConn1, err := conn.ReconnectingPTY(ctx, id, 100, 100, "bash")
+			netConn1, err := conn.ReconnectingPTY(ctx, id, 80, 80, "bash")
 			require.NoError(t, err)
 			defer netConn1.Close()
 
 			// A second simultaneous connection.
-			netConn2, err := conn.ReconnectingPTY(ctx, id, 100, 100, "bash")
+			netConn2, err := conn.ReconnectingPTY(ctx, id, 80, 80, "bash")
 			require.NoError(t, err)
 			defer netConn2.Close()
 
@@ -1674,7 +1674,7 @@ func TestAgent_ReconnectingPTY(t *testing.T) {
 
 			_ = netConn1.Close()
 			_ = netConn2.Close()
-			netConn3, err := conn.ReconnectingPTY(ctx, id, 100, 100, "bash")
+			netConn3, err := conn.ReconnectingPTY(ctx, id, 80, 80, "bash")
 			require.NoError(t, err)
 			defer netConn3.Close()
 
@@ -1698,7 +1698,7 @@ func TestAgent_ReconnectingPTY(t *testing.T) {
 			require.ErrorIs(t, testutil.ReadUntil(ctx, t, netConn3, nil), io.EOF)
 
 			// Try a non-shell command.  It should output then immediately exit.
-			netConn4, err := conn.ReconnectingPTY(ctx, uuid.New(), 100, 100, "echo test")
+			netConn4, err := conn.ReconnectingPTY(ctx, uuid.New(), 80, 80, "echo test")
 			require.NoError(t, err)
 			defer netConn4.Close()
 
diff --git a/coderd/workspaceapps/apptest/apptest.go b/coderd/workspaceapps/apptest/apptest.go
@@ -64,8 +64,8 @@ func Run(t *testing.T, appHostIsPrimary bool, factory DeploymentFactory) {
 			testReconnectingPTY(ctx, t, client, codersdk.WorkspaceAgentReconnectingPTYOpts{
 				AgentID:   appDetails.Agent.ID,
 				Reconnect: uuid.New(),
-				Height:    80,
-				Width:     80,
+				Height:    100,
+				Width:     1000,
 				Command:   "bash",
 			})
 		})
@@ -98,8 +98,8 @@ func Run(t *testing.T, appHostIsPrimary bool, factory DeploymentFactory) {
 			testReconnectingPTY(ctx, t, unauthedAppClient, codersdk.WorkspaceAgentReconnectingPTYOpts{
 				AgentID:     appDetails.Agent.ID,
 				Reconnect:   uuid.New(),
-				Height:      80,
-				Width:       80,
+				Height:      100,
+				Width:       100,
 				Command:     "bash",
 				SignedToken: issueRes.SignedToken,
 			})
@@ -1360,8 +1360,8 @@ func testReconnectingPTY(ctx context.Context, t *testing.T, client *codersdk.Cli
 	// First attempt to resize the TTY.
 	// The websocket will close if it fails!
 	data, err := json.Marshal(codersdk.ReconnectingPTYRequest{
-		Height: 250,
-		Width:  250,
+		Height: 80,
+		Width:  80,
 	})
 	require.NoError(t, err)
 	_, err = conn.Write(data)
diff --git a/testutil/pty.go b/testutil/pty.go
@@ -10,7 +10,8 @@ import (
 )
 
 // ReadUntilString emulates a terminal and reads one byte at a time until we
-// either see the string we want, or the context expires.
+// either see the string we want, or the context expires.  The PTY must be sized
+// to 80x80 or there could be unexpected results.
 func ReadUntilString(ctx context.Context, t *testing.T, want string, r io.Reader) error {
 	return ReadUntil(ctx, t, r, func(line string) bool {
 		return strings.TrimSpace(line) == want
@@ -19,6 +20,7 @@ func ReadUntilString(ctx context.Context, t *testing.T, want string, r io.Reader
 
 // ReadUntil emulates a terminal and reads one byte at a time until the matcher
 // returns true or the context expires.  If the matcher is nil, read until EOF.
+// The PTY must be sized to 80x80 or there could be unexpected results.
 func ReadUntil(ctx context.Context, t *testing.T, r io.Reader, matcher func(line string) bool) error {
 	// output can contain virtual terminal sequences, so we need to parse these
 	// to correctly interpret getting what we want.
