diff --git a/module/core/format_tools/src/format/print.rs b/module/core/format_tools/src/format/print.rs
index bc49db448d..78ac91b294 100644
--- a/module/core/format_tools/src/format/print.rs
+++ b/module/core/format_tools/src/format/print.rs
@@ -658,4 +658,4 @@ pub mod prelude
   use super::*;
 }
 
-//
\ No newline at end of file
+//
diff --git a/module/core/format_tools/tests/inc/print_test.rs b/module/core/format_tools/tests/inc/print_test.rs
new file mode 100644
index 0000000000..dd45f73de8
--- /dev/null
+++ b/module/core/format_tools/tests/inc/print_test.rs
@@ -0,0 +1,191 @@
+#[ allow( unused_imports ) ]
+use super::*;
+
+use the_module::
+{
+  Fields,
+  IteratorTrait,
+  AsTable,
+  Cells,
+  TableSize,
+  TableRows,
+  TableHeader,
+  Context,
+  WithRef,
+  MaybeAs,
+};
+
+use std::
+{
+  collections::HashMap,
+  borrow::Cow,
+};
+
+/// Struct representing a test object with various fields.
+#[ derive( Clone, Debug ) ]
+pub struct TestObject
+{
+  pub id : String,
+  pub created_at : i64,
+  pub file_ids : Vec< String >,
+  pub tools : Option< Vec< HashMap< String, String > > >,
+}
+
+impl Fields< &'static str, MaybeAs< '_, str, WithRef > >
+for TestObject
+{
+  type Value< 'v > = MaybeAs< 'v, str, WithRef >;
+
+  fn fields( &self ) -> impl IteratorTrait< Item = ( &'static str, MaybeAs< '_, str, WithRef > ) >
+  {
+    // use format_tools::ref_or_display_or_debug_multiline::field;
+    use format_tools::ref_or_display_or_debug::field;
+    let mut dst : Vec< ( &'static str, MaybeAs< '_, str, WithRef > ) > = Vec::new();
+
+    dst.push( field!( &self.id ) );
+    dst.push( field!( &self.created_at ) );
+    dst.push( field!( &self.file_ids ) );
+
+    if let Some( tools ) = &self.tools
+    {
+      dst.push( field!( tools ) );
+    }
+    else
+    {
+      dst.push( ( "tools", MaybeAs::none() ) );
+    }
+
+    dst.into_iter()
+  }
+}
+
+//
+
+fn test_objects_gen() -> Vec< TestObject >
+{
+
+  vec!
+  [
+    TestObject
+    {
+      id : "1".to_string(),
+      created_at : 1627845583,
+      file_ids : vec![ "file1".to_string(), "file2".to_string() ],
+      tools : None
+    },
+    TestObject
+    {
+      id : "2".to_string(),
+      created_at : 13,
+      file_ids : vec![ "file3".to_string(), "file4\nmore details".to_string() ],
+      tools : Some
+      (
+        vec!
+        [
+          {
+            let mut map = HashMap::new();
+            map.insert( "tool1".to_string(), "value1".to_string() );
+            map
+          },
+          {
+            let mut map = HashMap::new();
+            map.insert( "tool2".to_string(), "value2".to_string() );
+            map
+          }
+        ]
+      ),
+    },
+  ]
+
+}
+
+//
+
+#[ test ]
+fn table_to_string()
+// where
+  // for< 'a > AsTable< 'a, Vec< TestObject >, usize, TestObject, &'static str, String, &'static str > : TableFormatter< 'a >,
+{
+  use the_module::TableToString;
+  let test_objects = test_objects_gen();
+
+  let cells = Cells::< &'static str, WithRef >::cells( &test_objects[ 0 ] );
+  assert_eq!( cells.len(), 4 );
+  let cells = Cells::< &'static str, WithRef >::cells( &test_objects[ 1 ] );
+  assert_eq!( cells.len(), 4 );
+  drop( cells );
+
+  let as_table : AsTable< '_, Vec< TestObject >, usize, TestObject, &str, WithRef > = AsTable::new( &test_objects );
+  let size = TableSize::mcells( &as_table );
+  assert_eq!( size, [ 2, 4 ] );
+  let rows = TableRows::rows( &as_table );
+  assert_eq!( rows.len(), 2 );
+  dbg!( rows.collect::< Vec< _ > >() );
+  let header = TableHeader::header( &as_table );
+  assert!( header.is_some() );
+  let header = header.unwrap();
+  assert_eq!( header.len(), 4 );
+  assert_eq!( header.clone().collect::< Vec< _ > >(), vec!
+  [
+    ( "id", Cow::Owned( "id".to_string() ) ),
+    ( "created_at", Cow::Owned( "created_at".to_string() ) ),
+    ( "file_ids", Cow::Owned( "file_ids".to_string() ) ),
+    ( "tools", Cow::Owned( "tools".to_string() ) )
+  ]);
+  dbg!( header.collect::< Vec< _ > >() );
+
+  let mut output = String::new();
+  let mut context = Context::new( &mut output, Default::default() );
+  let got = the_module::TableFormatter::fmt( &as_table, &mut context );
+  assert!( got.is_ok() );
+  println!( "{}", &output );
+
+  // with explicit arguments
+
+  let as_table : AsTable< '_, Vec< TestObject >, usize, TestObject, &str, WithRef > = AsTable::new( &test_objects );
+  let table_string = as_table.table_to_string();
+  assert!( table_string.contains( "id" ) );
+  assert!( table_string.contains( "created_at" ) );
+  assert!( table_string.contains( "file_ids" ) );
+  assert!( table_string.contains( "tools" ) );
+
+  // without explicit arguments
+
+  println!( "" );
+  let as_table = AsTable::new( &test_objects );
+  let table_string = as_table.table_to_string();
+  assert!( table_string.contains( "id" ) );
+  assert!( table_string.contains( "created_at" ) );
+  assert!( table_string.contains( "file_ids" ) );
+  assert!( table_string.contains( "tools" ) );
+  println!( "{table_string}" );
+
+}
+
+#[ test ]
+fn custom_formatter()
+{
+  // use the_module::TableToString;
+  let test_objects = test_objects_gen();
+
+  let mut output = String::new();
+  let mut formatter = the_module::Styles::default();
+  formatter.cell_separator = " | ".into();
+  formatter.row_prefix = "> ".into();
+  formatter.row_postfix = " <".into();
+
+  let as_table = AsTable::new( &test_objects );
+  let mut context = Context::new( &mut output, formatter );
+  let got = the_module::TableFormatter::fmt( &as_table, &mut context );
+  assert!( got.is_ok() );
+  // let table_string = got.unwrap();
+
+  assert!( output.contains( "id" ) );
+  assert!( output.contains( "created_at" ) );
+  assert!( output.contains( "file_ids" ) );
+  assert!( output.contains( "tools" ) );
+  println!( "{output}" );
+
+}
+
+// xxx