Add dummy UDFs for sqlintegration

Author: alamb

datafusion/sql/tests/sql_integration.rs

@@ -15,6 +15,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
+use std::any::Any;
 #[cfg(test)]
 use std::collections::HashMap;
 use std::{sync::Arc, vec};
@@ -29,7 +30,8 @@ use datafusion_common::{
 use datafusion_common::{plan_err, ParamValues};
 use datafusion_expr::{
     logical_plan::{LogicalPlan, Prepare},
-    AggregateUDF, ScalarUDF, TableSource, WindowUDF,
+    AggregateUDF, ColumnarValue, ScalarUDF, ScalarUDFImpl, Signature, TableSource,
+    Volatility, WindowUDF,
 };
 use datafusion_sql::{
     parser::DFParser,
@@ -2671,13 +2673,62 @@ fn logical_plan_with_dialect_and_options(
     dialect: &dyn Dialect,
     options: ParserOptions,
 ) -> Result<LogicalPlan> {
-    let context = MockContextProvider::default();
+    let context = MockContextProvider::default().with_udf(make_udf(
+        "nullif",
+        vec![DataType::Int32, DataType::Int32],
+        DataType::Int32,
+    ));
+
     let planner = SqlToRel::new_with_options(&context, options);
     let result = DFParser::parse_sql_with_dialect(sql, dialect);
     let mut ast = result?;
     planner.statement_to_plan(ast.pop_front().unwrap())
 }
 
+fn make_udf(name: &'static str, args: Vec<DataType>, return_type: DataType) -> ScalarUDF {
+    ScalarUDF::new_from_impl(DummyUDF::new(name, args, return_type))
+}
+
+/// Mocked UDF
+#[derive(Debug)]
+struct DummyUDF {
+    name: &'static str,
+    signature: Signature,
+    return_type: DataType,
+}
+
+impl DummyUDF {
+    fn new(name: &'static str, args: Vec<DataType>, return_type: DataType) -> Self {
+        Self {
+            name,
+            signature: Signature::exact(args, Volatility::Immutable),
+            return_type,
+        }
+    }
+}
+
+impl ScalarUDFImpl for DummyUDF {
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+
+    fn name(&self) -> &str {
+        &self.name
+    }
+
+    fn signature(&self) -> &Signature {
+        &self.signature
+    }
+
+    fn return_type(&self, arg_types: &[DataType]) -> Result<DataType> {
+        Ok(self.return_type.clone())
+    }
+
+    fn invoke(&self, args: &[ColumnarValue]) -> Result<ColumnarValue> {
+        unimplemented!("DummyUDF::invoke")
+    }
+}
+
 /// Create logical plan, write with formatter, compare to expected output
 fn quick_test(sql: &str, expected: &str) {
     let plan = logical_plan(sql).unwrap();
@@ -2724,13 +2775,19 @@ fn prepare_stmt_replace_params_quick_test(
 #[derive(Default)]
 struct MockContextProvider {
     options: ConfigOptions,
+    udfs: HashMap<String, Arc<ScalarUDF>>,
     udafs: HashMap<String, Arc<AggregateUDF>>,
 }
 
 impl MockContextProvider {
     fn options_mut(&mut self) -> &mut ConfigOptions {
         &mut self.options
     }
+
+    fn with_udf(mut self, udf: ScalarUDF) -> Self {
+        self.udfs.insert(udf.name().to_string(), Arc::new(udf));
+        self
+    }
 }
 
 impl ContextProvider for MockContextProvider {
@@ -2823,8 +2880,8 @@ impl ContextProvider for MockContextProvider {
         }
     }
 
-    fn get_function_meta(&self, _name: &str) -> Option<Arc<ScalarUDF>> {
-        None
+    fn get_function_meta(&self, name: &str) -> Option<Arc<ScalarUDF>> {
+        self.udfs.get(name).map(Arc::clone)
     }
 
     fn get_aggregate_meta(&self, name: &str) -> Option<Arc<AggregateUDF>> {