Add test harness for CockroachDB, convert examples to tests

.envrc

@@ -0,0 +1,4 @@
+# For use with direnv: https://direnv.net
+# See also: ./env.sh
+
+PATH_add out/cockroachdb/bin

.github/workflows/rust.yml

@@ -31,6 +31,10 @@ jobs:
     steps:
     # actions/checkout@v2
     - uses: actions/checkout@72f2cec99f417b1a1c5e2e88945068983b7965f9
+    - name: Download CockroachDB
+      run: ./tools/ci_download_cockroachdb
+    - name: Add CockroachDB to PATH
+      run: echo ./out/cockroachdb/bin >> $GITHUB_PATH
     - name: Build
       run: cargo build --tests --verbose
     - name: Run tests

.gitignore

@@ -1,2 +1,3 @@
 /target
 Cargo.lock
+out

Cargo.toml

@@ -16,5 +16,9 @@ thiserror = "1.0"
 tokio = { version = "1.32", default-features = false, features = [ "rt-multi-thread" ] }
 
 [dev-dependencies]
+anyhow = "1.0"
 diesel = { version = "2.1.0", features = [ "postgres", "r2d2" ] }
-tokio = { version = "1.32", features = [ "macros"] }
+libc = "0.2.150"
+tempfile = "3.8"
+tokio = { version = "1.32", features = [ "macros", "fs", "process" ] }
+tokio-postgres = { version = "0.7", features = [ "with-chrono-0_4", "with-uuid-1" ] }

src/async_traits.rs

@@ -131,7 +131,7 @@ where
                 .await
                 {
                     Ok(()) => Err(user_error),
-                    Err(err) => Err(err.into()),
+                    Err(err) => Err(err),
                 }
             }
         }

src/error.rs

@@ -40,7 +40,7 @@ impl<T> OptionalExtension<T> for Result<T, ConnectionError> {
 
         self_as_query_result
             .optional()
-            .map_err(|e| ConnectionError::Query(e))
+            .map_err(ConnectionError::Query)
     }
 }
 

tests/README.md

@@ -0,0 +1,15 @@
+# Tests
+
+This directory includes some integration tests, specifically with the
+CockroachDB database, which uses a PostgreSQL protocol.
+
+Tests expect that the CockroachDB binary exist, and fail without it.
+
+To download a local copy of CockroachDB:
+
+```bash
+./tools/ci_download_cockroachdb
+```
+
+This downloads a binary to `./out/cockroachdb/bin/cockoach`. If you'd like
+to use your own binary here, replace this binary with your own executable.