Add test to ensure tera templates are in sync (#1879)

closes #1878

exercises/practice/knapsack/tests/knapsack.rs

@@ -1,6 +1,16 @@
 use knapsack::*;
 
 #[test]
+fn test_no_items() {
+    let max_weight = 100;
+    let items = [];
+    let output = maximum_value(max_weight, &items);
+    let expected = 0;
+    assert_eq!(output, expected);
+}
+
+#[test]
+#[ignore]
 fn test_one_item_too_heavy() {
     let max_weight = 10;
     let items = [Item {

exercises/practice/queen-attack/.meta/test_template.tera

@@ -1,4 +1,4 @@
-use queen_attack::{ChessPiece, ChessPosition, Queen};
+use queen_attack::*;
 
 {% for test in cases %}
 #[test]

exercises/practice/variable-length-quantity/.meta/test_template.tera

@@ -7,7 +7,7 @@ use variable_length_quantity as vlq;
 fn {{ test.description | slugify | replace(from="-", to="_") }}() {
 {%- if test.property == "encode" %}
     let input = &{{ test.input.integers | json_encode() }};
-    let output = vlq::{{ fn_names[0] }}(input);
+    let output = vlq::to_bytes(input);
     let expected = vec![
         {%- for byte in test.expected -%}
             0x{{ byte | to_hex }},
@@ -19,7 +19,7 @@ fn {{ test.description | slugify | replace(from="-", to="_") }}() {
             0x{{ byte | to_hex }},
         {%- endfor -%}
     ];
-    let output = vlq::{{ fn_names[1] }}(input);
+    let output = vlq::from_bytes(input);
     let expected = {% if test.expected is object -%}
         Err(vlq::Error::IncompleteNumber)
     {%- else -%}

exercises/practice/wordy/.meta/additional-tests.json

@@ -0,0 +1,28 @@
+[
+  {
+    "uuid": "88bf4b28-0de3-4883-93c7-db1b14aa806e",
+    "description": "exponential",
+    "comments": [
+      "This test case was added a long time ago.",
+      "Upstreaming it would make the exercise more difficult."
+    ],
+    "property": "exponentials",
+    "input": {
+      "question": "What is 2 raised to the 5th power?"
+    },
+    "expected": 32
+  },
+  {
+    "uuid": "bb8c655c-cf42-4dfc-90e0-152fcfd8d4e0",
+    "description": "addition and exponential",
+    "comments": [
+      "This test case was added a long time ago.",
+      "Upstreaming it would make the exercise more difficult."
+    ],
+    "property": "exponentials",
+    "input": {
+      "question": "What is 1 plus 2 raised to the 2nd power?"
+    },
+    "expected": 9
+  }
+]

exercises/practice/wordy/.meta/test_template.tera

@@ -3,8 +3,11 @@
 {% if loop.index != 1 -%}
 #[ignore]
 {% endif -%}
+{% if test.property == "exponentials" -%}
+#[cfg(feature = "exponentials")]
+{% endif -%}
 fn {{ test.description | slugify | replace(from="-", to="_") }}() {
-    let input = {{ test.input | json_encode() }};
+    let input = {{ test.input.question | json_encode() }};
     let output = {{ crate_name }}::{{ fn_names[0] }}(input);
     let expected = {% if test.expected is object -%}
         None

rust-tooling/generate/src/exercise_generation.rs → rust-tooling/generate/src/lib.rs

@@ -162,3 +162,22 @@ It probably generates invalid Rust code."
 pub fn get_test_template(slug: &str) -> Option<Tera> {
     Some(Tera::new(format!("exercises/practice/{slug}/.meta/*.tera").as_str()).unwrap())
 }
+
+pub fn read_fn_names_from_lib_rs(slug: &str) -> Vec<String> {
+    let lib_rs =
+        std::fs::read_to_string(format!("exercises/practice/{}/src/lib.rs", slug)).unwrap();
+
+    lib_rs
+        .split("fn ")
+        .skip(1)
+        .map(|f| {
+            let tmp = f.split_once('(').unwrap().0;
+            // strip generics
+            if let Some((res, _)) = tmp.split_once('<') {
+                res.to_string()
+            } else {
+                tmp.to_string()
+            }
+        })
+        .collect()
+}

rust-tooling/generate/src/main.rs

@@ -5,7 +5,6 @@ use cli::{AddArgs, FullAddArgs, UpdateArgs};
 use models::track_config::{self, TRACK_CONFIG};
 
 mod cli;
-mod exercise_generation;
 
 fn main() {
     utils::fs::cd_into_repo_root();
@@ -79,12 +78,12 @@ fn make_configlet_generate_what_it_can(slug: &str) {
 
 fn generate_exercise_files(slug: &str, is_update: bool) {
     let fn_names = if is_update {
-        read_fn_names_from_lib_rs(slug)
+        generate::read_fn_names_from_lib_rs(slug)
     } else {
         vec!["TODO".to_string()]
     };
 
-    let exercise = exercise_generation::new(slug, fn_names);
+    let exercise = generate::new(slug, fn_names);
 
     let exercise_path = PathBuf::from("exercises/practice").join(slug);
 
@@ -108,22 +107,3 @@ fn generate_exercise_files(slug: &str, is_update: bool) {
     )
     .unwrap();
 }
-
-fn read_fn_names_from_lib_rs(slug: &str) -> Vec<String> {
-    let lib_rs =
-        std::fs::read_to_string(format!("exercises/practice/{}/src/lib.rs", slug)).unwrap();
-
-    lib_rs
-        .split("fn ")
-        .skip(1)
-        .map(|f| {
-            let tmp = f.split_once('(').unwrap().0;
-            // strip generics
-            if let Some((res, _)) = tmp.split_once('<') {
-                res.to_string()
-            } else {
-                tmp.to_string()
-            }
-        })
-        .collect()
-}

rust-tooling/generate/tests/tera_templates_are_in_sync.rs

@@ -0,0 +1,23 @@
+//! This test is not run in CI. Doing so would slow down CI noticeably, because
+//! exercise generation depends on `tera`, which takes a while to compile.
+
+use glob::glob;
+use utils::fs::cd_into_repo_root;
+
+#[test]
+fn tera_templates_are_in_sync() {
+    cd_into_repo_root();
+    for entry in glob("exercises/*/*/.meta/test_template.tera").unwrap() {
+        let path = entry.unwrap();
+        let exercise_dir = path.parent().unwrap().parent().unwrap();
+        let slug = exercise_dir.file_name().unwrap().to_string_lossy();
+
+        let fn_names = generate::read_fn_names_from_lib_rs(&slug);
+        let generated = generate::new(&slug, fn_names);
+
+        let test_path = exercise_dir.join("tests").join(format!("{slug}.rs"));
+        let on_disk = std::fs::read_to_string(test_path).unwrap();
+
+        assert_eq!(generated.tests, on_disk);
+    }
+}