From 38bcc7d01ac405c17f392b6aa20fcef827f2e497 Mon Sep 17 00:00:00 2001
From: "David E. Wheeler" <david@justatheory.com>
Date: Fri, 6 Sep 2024 17:29:24 -0400
Subject: [PATCH] Test merging happy path

---
 src/meta/mod.rs   |  16 ++++---
 src/meta/tests.rs | 109 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 120 insertions(+), 5 deletions(-)

diff --git a/src/meta/mod.rs b/src/meta/mod.rs
index f2cd748..1f13c83 100644
--- a/src/meta/mod.rs
+++ b/src/meta/mod.rs
@@ -298,20 +298,26 @@ impl TryFrom<Value> for Meta {
     }
 }
 
-impl TryFrom<&[Value]> for Meta {
+impl TryFrom<&[&Value]> for Meta {
     type Error = Box<dyn Error>;
-    fn try_from(meta: &[Value]) -> Result<Self, Self::Error> {
+    // Merge multiple spec values into a single Meta object. The first value
+    // in `meta` should be the primary metadata, generally included in a
+    // distribution. Subsequent values will be merged into that first value
+    // via the [RFC 7396] merge pattern.
+    //
+    // [RFC 7396]: https://www.rfc-editor.org/rfc/rfc7396.html
+    fn try_from(meta: &[&Value]) -> Result<Self, Self::Error> {
         if meta.is_empty() {
             return Err(Box::from("meta contains no values"));
         }
 
         // Find the version of the first doc.
         let version =
-            util::get_version(&meta[0]).ok_or("no spec version found in first meta value")?;
+            util::get_version(meta[0]).ok_or("no spec version found in first meta value")?;
 
         // Convert the first doc to v2 if necessary.
         let mut v2 = match version {
-            1 => v1::to_v2(&meta[0])?,
+            1 => v1::to_v2(meta[0])?,
             2 => meta[0].clone(),
             _ => return Err(Box::from(format!("Unknown meta version {version}"))),
         };
@@ -324,7 +330,7 @@ impl TryFrom<&[Value]> for Meta {
         // Validate the patched doc and return.
         let mut validator = crate::valid::Validator::new();
         validator.validate(&v2).map_err(|e| e.to_string())?;
-        Meta::from_version(version, v2)
+        Meta::from_version(2, v2)
     }
 }
 
diff --git a/src/meta/tests.rs b/src/meta/tests.rs
index cf5b0b5..8a742dd 100644
--- a/src/meta/tests.rs
+++ b/src/meta/tests.rs
@@ -105,3 +105,112 @@ fn test_bad_corpus() -> Result<(), Box<dyn Error>> {
 
     Ok(())
 }
+
+#[test]
+fn test_try_merge_v1() -> Result<(), Box<dyn Error>> {
+    // Load a v1 META file.
+    let dir: PathBuf = [env!("CARGO_MANIFEST_DIR"), "corpus"].iter().collect();
+    let widget_file = dir.join("v1").join("widget.json");
+    let contents: Value = serde_json::from_reader(File::open(&widget_file)?)?;
+
+    // expect maps a JSON pointer to an expected value.
+    for (name, patch, expect) in [
+        (
+            "license",
+            json!({"license": "MIT"}),
+            json!({"/license": "MIT"}),
+        ),
+        (
+            "tle",
+            json!({"contents": {"extensions": {"widget": {"tle": true}}}}),
+            json!({"/contents/extensions/widget": {
+                "control": "widget.control",
+                "sql": "sql/widget.sql.in",
+                "tle": true,
+            }}),
+        ),
+        (
+            "categories",
+            json!({"classifications": {"categories": ["Analytics", "Connectors"]}}),
+            json!({"/classifications/categories": ["Analytics", "Connectors"]}),
+        ),
+        (
+            "tags",
+            json!({"classifications": {"tags": ["hi", "go", "ick"]}}),
+            json!({"/classifications/tags": ["hi", "go", "ick"]}),
+        ),
+        (
+            "resources",
+            json!({"resources": {
+                "issues": "https://example.com/issues",
+                "repository": "https://example.com/repo",
+            }}),
+            json!({"/resources": {
+                "homepage": "http://widget.example.org/",
+                "issues": "https://example.com/issues",
+                "repository": "https://example.com/repo",
+            }}),
+        ),
+    ] {
+        run_merge_case(name, &contents, &patch, &expect)?;
+    }
+
+    Ok(())
+}
+
+#[test]
+fn test_try_merge_v2() -> Result<(), Box<dyn Error>> {
+    // Load a v2 META file.
+    let dir: PathBuf = [env!("CARGO_MANIFEST_DIR"), "corpus"].iter().collect();
+    let widget_file = dir.join("v2").join("minimal.json");
+    let contents: Value = serde_json::from_reader(File::open(&widget_file)?)?;
+
+    // expect maps a JSON pointer to an expected value.
+    for (name, patch, expect) in [
+        (
+            "license",
+            json!({"license": "MIT"}),
+            json!({"/license": "MIT"}),
+        ),
+        (
+            "tle",
+            json!({"contents": {"extensions": {"pair": {"tle": true}}}}),
+            json!({"/contents/extensions/pair": {
+                "sql": "sql/pair.sql",
+                "control": "pair.control",
+                "tle": true,
+            }}),
+        ),
+    ] {
+        run_merge_case(name, &contents, &patch, &expect)?;
+    }
+
+    Ok(())
+}
+
+fn run_merge_case(
+    name: &str,
+    orig: &Value,
+    patch: &Value,
+    expect: &Value,
+) -> Result<(), Box<dyn Error>> {
+    let meta = vec![orig, patch];
+    match Meta::try_from(meta.as_slice()) {
+        Err(e) => panic!("widget.json patching {name} failed: {e}"),
+        Ok(m) => {
+            // Convert the Meta object to JSON.
+            let output: Result<Value, Box<dyn Error>> = m.try_into();
+            match output {
+                Err(e) => panic!("widget.json {name} serialization failed: {e}"),
+                Ok(val) => {
+                    // Compare expected values at pointers.
+                    for (p, v) in expect.as_object().unwrap() {
+                        assert_eq!(v, val.pointer(p).unwrap())
+                    }
+                }
+            }
+        }
+    }
+
+    Ok(())
+}