fix(visualization, v1.2): define the render_error the table charts already call

common/workflow-operator/src/main/scala/org/apache/texera/amber/operator/visualization/figureFactoryTable/FigureFactoryTableOpDesc.scala

@@ -96,6 +96,9 @@ class FigureFactoryTableOpDesc extends PythonOperatorDescriptor {
        |
        |class TableChartOperator(UDFTableOperator):
        |
+       |    def render_error(self, error_msg) -> str:
+       |        return f"<h1>Figure Factory Table is not available.</h1><p>Reason is: {error_msg}</p>"
+       |
        |    def process_table(self, table: Table, port: int) -> Iterator[Optional[TableLike]]:
        |
        |        if table.empty:

common/workflow-operator/src/main/scala/org/apache/texera/amber/operator/visualization/tablesChart/TablesPlotOpDesc.scala

@@ -76,6 +76,9 @@ class TablesPlotOpDesc extends PythonOperatorDescriptor {
        |import plotly.io
        |class TableChartOperator(UDFTableOperator):
        |
+       |    def render_error(self, error_msg) -> str:
+       |        return f"<h1>Tables Plot is not available.</h1><p>Reason is: {error_msg}</p>"
+       |
        |    def process_table(self, table: Table, port: int) -> Iterator[Optional[TableLike]]:
        |
        |        if table.empty:

common/workflow-operator/src/test/scala/org/apache/texera/amber/operator/visualization/figureFactoryTable/FigureFactoryTableOpDescSpec.scala

@@ -0,0 +1,113 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.texera.amber.operator.visualization.figureFactoryTable
+
+import org.scalatest.BeforeAndAfter
+import org.scalatest.flatspec.AnyFlatSpec
+import org.scalatest.matchers.should.Matchers
+
+import java.nio.charset.StandardCharsets
+import java.util.Base64
+
+class FigureFactoryTableOpDescSpec extends AnyFlatSpec with BeforeAndAfter with Matchers {
+
+  var opDesc: FigureFactoryTableOpDesc = _
+
+  before {
+    opDesc = new FigureFactoryTableOpDesc()
+  }
+
+  private def b64(s: String): String =
+    Base64.getEncoder.encodeToString(s.getBytes(StandardCharsets.UTF_8))
+
+  private def carries(output: String, name: String): Boolean =
+    output.contains(name) || output.contains(b64(name))
+
+  private def column(name: String): FigureFactoryTableConfig = {
+    val config = new FigureFactoryTableConfig()
+    config.attributeName = name
+    config
+  }
+
+  private def withColumns(): Unit =
+    opDesc.columns = List(column("col_one"), column("col_two"))
+
+  it should "throw AssertionError with a 'cannot be empty' message when columns list is empty (manipulateTable)" in {
+    val ex = intercept[AssertionError](opDesc.manipulateTable())
+    ex.getMessage should not be null
+    ex.getMessage should include("cannot be empty")
+  }
+
+  it should "throw AssertionError with a 'cannot be empty' message when columns list is empty (createFigureFactoryTablePlotlyFigure)" in {
+    val ex = intercept[AssertionError](opDesc.createFigureFactoryTablePlotlyFigure())
+    ex.getMessage should not be null
+    ex.getMessage should include("cannot be empty")
+  }
+
+  it should "throw AssertionError mentioning 'at least 30' when rowHeight is below 30" in {
+    withColumns()
+    opDesc.rowHeight = 10.0
+    val ex = intercept[AssertionError](opDesc.createFigureFactoryTablePlotlyFigure())
+    ex.getMessage should not be null
+    ex.getMessage should include("at least 30")
+  }
+
+  it should "throw AssertionError mentioning 'non-negative' when fontSize is negative" in {
+    withColumns()
+    opDesc.fontSize = -1.0
+    val ex = intercept[AssertionError](opDesc.createFigureFactoryTablePlotlyFigure())
+    ex.getMessage should not be null
+    ex.getMessage should include("non-negative")
+  }
+
+  it should "not throw with default fontSize (12) and rowHeight (30) once columns are set" in {
+    withColumns()
+    val plain = opDesc.createFigureFactoryTablePlotlyFigure().plain
+    assert(carries(plain, "col_one"))
+    assert(carries(plain, "col_two"))
+    plain should include("ff.create_table")
+  }
+
+  it should "accept boundary values rowHeight = 30 and fontSize = 0" in {
+    withColumns()
+    opDesc.rowHeight = 30.0
+    opDesc.fontSize = 0.0
+    noException should be thrownBy opDesc.createFigureFactoryTablePlotlyFigure()
+  }
+
+  it should "generate python code carrying the configured columns" in {
+    withColumns()
+    val code = opDesc.generatePythonCode()
+    assert(carries(code, "col_one"))
+    assert(carries(code, "col_two"))
+    code should include("class TableChartOperator(UDFTableOperator)")
+  }
+
+  it should "define the render_error the empty-table branches call" in {
+    // Both empty-table branches call self.render_error; without the definition they
+    // raised AttributeError instead of rendering the message.
+    withColumns()
+    val code = opDesc.generatePythonCode()
+    code should include("def render_error(self, error_msg) -> str:")
+    code should include(
+      """return f"<h1>Figure Factory Table is not available.</h1><p>Reason is: {error_msg}</p>""""
+    )
+  }
+}

common/workflow-operator/src/test/scala/org/apache/texera/amber/operator/visualization/tablesChart/TablesPlotOpDescSpec.scala

@@ -0,0 +1,102 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.texera.amber.operator.visualization.tablesChart
+
+import org.scalatest.BeforeAndAfter
+import org.scalatest.flatspec.AnyFlatSpec
+import org.scalatest.matchers.should.Matchers
+
+import java.nio.charset.StandardCharsets
+import java.util.Base64
+
+class TablesPlotOpDescSpec extends AnyFlatSpec with BeforeAndAfter with Matchers {
+
+  var opDesc: TablesPlotOpDesc = _
+
+  before {
+    opDesc = new TablesPlotOpDesc()
+  }
+
+  private def b64(s: String): String =
+    Base64.getEncoder.encodeToString(s.getBytes(StandardCharsets.UTF_8))
+
+  private def carries(output: String, name: String): Boolean =
+    output.contains(name) || output.contains(b64(name))
+
+  private def column(name: String): TablesConfig = {
+    val config = new TablesConfig()
+    config.attributeName = name
+    config
+  }
+
+  it should "throw AssertionError with a 'cannot be empty' message when included columns list is empty (manipulateTable)" in {
+    val ex = intercept[AssertionError](opDesc.manipulateTable())
+    ex.getMessage should not be null
+    ex.getMessage should include("cannot be empty")
+  }
+
+  it should "throw AssertionError with a 'cannot be empty' message when included columns list is empty (createPlotlyFigure)" in {
+    val ex = intercept[AssertionError](opDesc.createPlotlyFigure())
+    ex.getMessage should not be null
+    ex.getMessage should include("cannot be empty")
+  }
+
+  it should "render the configured columns when the included columns list is set" in {
+    opDesc.includedColumns = List(column("col_one"), column("col_two"))
+    val tablePlain = opDesc.manipulateTable().plain
+    assert(carries(tablePlain, "col_one"))
+    assert(carries(tablePlain, "col_two"))
+
+    val figurePlain = opDesc.createPlotlyFigure().plain
+    assert(carries(figurePlain, "col_one"))
+    assert(carries(figurePlain, "col_two"))
+    figurePlain should include("go.Table")
+  }
+
+  it should "generate python code carrying the configured columns" in {
+    opDesc.includedColumns = List(column("col_one"), column("col_two"))
+    val code = opDesc.generatePythonCode()
+    assert(carries(code, "col_one"))
+    assert(carries(code, "col_two"))
+    code should include("class TableChartOperator(UDFTableOperator)")
+  }
+
+  it should "join multiple columns with a comma, not the literal ',' (valid Python)" in {
+    // Each column renders to a decode(...) call, so they must be comma-joined;
+    // joining with the literal ',' puts a string right after a call (invalid Python).
+    opDesc.includedColumns = List(column("col_one"), column("col_two"))
+    val code = opDesc.generatePythonCode()
+    code should include(
+      s"self.decode_python_template('${b64("col_one")}'),self.decode_python_template('${b64("col_two")}')"
+    )
+    code should not include "')','"
+  }
+
+  it should "define the render_error the empty-table branches call" in {
+    // Both empty-table branches call self.render_error; without the definition they
+    // raised AttributeError instead of rendering the message.
+    opDesc.includedColumns = List(column("col_one"), column("col_two"))
+    val code = opDesc.generatePythonCode()
+    code should include("def render_error(self, error_msg) -> str:")
+    code should include(
+      """return f"<h1>Tables Plot is not available.</h1><p>Reason is: {error_msg}</p>""""
+    )
+  }
+}