add snapshot test for display trait (#837)

* add snapshot test for display trait

* regenerate test

book/tests/snapshot.rs

@@ -17,8 +17,9 @@
 //
 use anyhow::{bail, Result};
 use globset::Glob;
-use insta::{assert_snapshot, glob};
+use insta::{assert_display_snapshot, assert_snapshot, glob};
 use log::warn;
+use prql_compiler::ast::Item;
 use prql_compiler::*;
 use pulldown_cmark::{CodeBlockKind, Event, Parser, Tag};
 use std::fs;
@@ -38,6 +39,7 @@ fn run_examples() -> Result<()> {
     #[cfg(not(target_family = "windows"))]
     write_reference_prql()?;
     run_reference_prql()?;
+    run_display_reference_prql()?;
 
     Ok(())
 }
@@ -131,3 +133,17 @@ fn run_reference_prql() -> Result<()> {
     });
     Ok(())
 }
+
+/// Snapshot the display trait output of each example.
+fn run_display_reference_prql() -> Result<()> {
+    glob!("prql/**/*.prql", |path| {
+        let prql = fs::read_to_string(path).unwrap();
+
+        if prql.contains("skip_test") {
+            return;
+        }
+
+        assert_display_snapshot!(Item::Query(parse(&prql).unwrap()));
+    });
+    Ok(())
+}

book/tests/snapshots/snapshot__run_display_reference_prql@aggregate-0.prql.snap

@@ -0,0 +1,14 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/transforms/aggregate-0.prql
+---
+prql dialect:generic
+
+from `employees`
+aggregate [
+  average `salary`,
+  ct = `count`,
+]
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@aggregate-1.prql.snap

@@ -0,0 +1,19 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/transforms/aggregate-1.prql
+---
+prql dialect:generic
+
+from `employees`
+group [
+  `title`,
+  `country`,
+] (
+  aggregate [
+  average `salary`,
+  ct = `count`,
+]
+)
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@coalesce-0.prql.snap

@@ -0,0 +1,13 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/language-features/coalesce-0.prql
+---
+prql dialect:generic
+
+from `orders`
+derive (
+  coalesce `amount` 0
+)
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@cte-0.prql.snap

@@ -0,0 +1,33 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/examples/cte-0.prql
+---
+prql dialect:generic
+
+table newest_employees = (
+  from `employees`
+  sort `tenure`
+  take 50
+)
+
+
+
+table average_salaries = (
+  from `salaries`
+  group `country` (
+  aggregate average_country_salary = (average `salary`)
+)
+)
+
+
+
+from `newest_employees`
+join `average_salaries` [`country`]
+select [
+  `name`,
+  `salary`,
+  `average_country_salary`,
+]
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@dates_and_times-0.prql.snap

@@ -0,0 +1,11 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/language-features/dates_and_times-0.prql
+---
+prql dialect:generic
+
+from `employees`
+derive age_at_year_end = @2022-12-31 - `dob`
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@dates_and_times-1.prql.snap

@@ -0,0 +1,11 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/language-features/dates_and_times-1.prql
+---
+prql dialect:generic
+
+from `orders`
+derive should_have_shipped_today = `order_time` < @08:30
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@dates_and_times-2.prql.snap

@@ -0,0 +1,10 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/language-features/dates_and_times-2.prql
+---
+prql dialect:generic
+
+derive first_prql_commit = @2020-01-01T13:19:55-0800
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@dates_and_times-3.prql.snap

@@ -0,0 +1,11 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/language-features/dates_and_times-3.prql
+---
+prql dialect:generic
+
+from `projects`
+derive first_check_in = `start` + 10days
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@derive-0.prql.snap

@@ -0,0 +1,11 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/transforms/derive-0.prql
+---
+prql dialect:generic
+
+from `employees`
+derive gross_salary = `salary` + `payroll_tax`
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@derive-1.prql.snap

@@ -0,0 +1,14 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/transforms/derive-1.prql
+---
+prql dialect:generic
+
+from `employees`
+derive [
+  gross_salary = `salary` + `payroll_tax`,
+  gross_cost = `gross_salary` + `benefits_cost`,
+]
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@derive-2.prql.snap

@@ -0,0 +1,10 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/transforms/derive-2.prql
+---
+prql dialect:generic
+
+derive x = 5
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@dialect_and_version-0.prql.snap

@@ -0,0 +1,12 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/queries/dialect_and_version-0.prql
+---
+prql dialect:postgres
+
+from `employees`
+sort `age`
+take 10
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@dialect_and_version-1.prql.snap

@@ -0,0 +1,12 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/queries/dialect_and_version-1.prql
+---
+prql dialect:mssql
+
+from `employees`
+sort `age`
+take 10
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@dialect_and_version-2.prql.snap

@@ -0,0 +1,10 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/queries/dialect_and_version-2.prql
+---
+prql dialect:generic version:1
+
+from `employees`
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@distinct-0.prql.snap

@@ -0,0 +1,14 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/language-features/distinct-0.prql
+---
+prql dialect:generic
+
+from `employees`
+select `department`
+group `department` (
+  take 1
+)
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@distinct-1.prql.snap

@@ -0,0 +1,14 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/language-features/distinct-1.prql
+---
+prql dialect:generic
+
+from `employees`
+select `department`
+group `department` (
+  take 1
+)
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@distinct-2.prql.snap

@@ -0,0 +1,14 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/language-features/distinct-2.prql
+---
+prql dialect:generic
+
+from `employees`
+group `department` (
+  sort `age`
+  take 1
+)
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@employees-0.prql.snap

@@ -0,0 +1,27 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/examples/employees-0.prql
+---
+prql dialect:generic
+
+from `salaries`
+group [`emp_no`] (
+  aggregate [emp_salary = (average `salary`)]
+)
+join t = `titles` [`emp_no`]
+join `dept_emp` side:`left` [`emp_no`]
+group [
+  `dept_emp.dept_no`,
+  `t.title`,
+] (
+  aggregate [avg_salary = (average `emp_salary`)]
+)
+join `departments` [`dept_no`]
+select [
+  `dept_name`,
+  `title`,
+  `avg_salary`,
+]
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@employees-1.prql.snap

@@ -0,0 +1,34 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/examples/employees-1.prql
+---
+prql dialect:generic
+
+from `employees`
+join `salaries` [`emp_no`]
+group [
+  `emp_no`,
+  `gender`,
+] (
+  aggregate [emp_salary = (average `salary`)]
+)
+join de = `dept_emp` [`emp_no`] side:`left`
+group [
+  `de.dept_no`,
+  `gender`,
+] (
+  aggregate [
+  salary_avg = (average `emp_salary`),
+  salary_sd = (stddev `emp_salary`),
+]
+)
+join `departments` [`dept_no`]
+select [
+  `dept_name`,
+  `gender`,
+  `salary_avg`,
+  `salary_sd`,
+]
+
+

book/tests/snapshots/snapshot__run_display_reference_prql@employees-2.prql.snap

@@ -0,0 +1,37 @@
+---
+source: book/tests/snapshot.rs
+expression: "Item::Query(parse(&prql).unwrap())"
+input_file: book/tests/prql/examples/employees-2.prql
+---
+prql dialect:generic
+
+from `employees`
+join `salaries` [`emp_no`]
+group [
+  `emp_no`,
+  `gender`,
+] (
+  aggregate [emp_salary = (average `salary`)]
+)
+join de = `dept_emp` [`emp_no`]
+join dm = `dept_manager` [`dm.dept_no` == `de.dept_no` and s"(de.from_date, de.to_date) OVERLAPS (dm.from_date, dm.to_date)"]
+group [
+  `dm.emp_no`,
+  `gender`,
+] (
+  aggregate [
+  salary_avg = (average `emp_salary`),
+  salary_sd = (stddev `emp_salary`),
+]
+)
+derive mng_no = `dm.emp_no`
+join managers = `employees` [`emp_no`]
+derive mng_name = s"managers.first_name || ' ' || managers.last_name"
+select [
+  `mng_name`,
+  `managers.gender`,
+  `salary_avg`,
+  `salary_sd`,
+]
+
+