Fix "no bin target" error and add a test

The build error was:

    error: no bin target named `pgrx_embed_clerk_fdw`.

This is a side-effect of pgrx v0.12.x; pgcentralfoundation/pgrx#1888
documents the fix: adding a no-op embed target in
`src/bin/pgrx_embed_clerk_fdw.rs` and setting `lib.crate-type` to:

    crate-type = ["cdylib", "lib"]

Hopefully this funky workaround can be removed in the future.

The test simply ensures that `CREATE EXTENSION` works; the update to
`extension_ci.yml` ensures it passes on all supported Postgres versions.

.github/workflows/extension_ci.yml

@@ -42,39 +42,26 @@ jobs:
       - name: Clippy
         run: cargo clippy
 
-  # figure out how to test work
-  # test:
-  #   name: Run tests
-  #   runs-on: ubuntu-22.04
-  #   steps:
-  #     - uses: actions/checkout@v2
-  #     - name: Install Rust stable toolchain
-  #       uses: actions-rs/toolchain@v1
-  #       with:
-  #         toolchain: stable
-  #     - uses: Swatinem/rust-cache@v2
-  #       with:
-  #         prefix-key: "pgmq-extension-test"
-  #         workspaces: |
-  #           pgmq
-  #         # Additional directories to cache
-  #         cache-directories: |
-  #           /home/runner/.pgrx
-  #     - uses: ./.github/actions/pgx-init
-  #       with:
-  #         working-directory: ./
-  #     - name: test
-  #       run: |
-  #         sudo apt-get update && sudo apt-get install -y postgresql-server-dev-14
-  #         git clone https://github.com/pgpartman/pg_partman.git && \
-  #         cd pg_partman && \
-  #         sudo make install && cd ../
-  #         cp /usr/share/postgresql/14/extension/pg_partman* ~/.pgrx/15.4/pgrx-install/share/postgresql/extension/
-  #         cp /usr/lib/postgresql/14/lib/pg_partman_bgw.so ~/.pgrx/15.4/pgrx-install/lib/postgresql/
-  #         rm -rf ./target/pgrx-test-data-* || true
-  #         pg_version=$(stoml Cargo.toml features.default)
-  #         cargo pgrx run ${pg_version} --pgcli || true
-  #         cargo pgrx test ${pg_version}
+  test:
+    runs-on: ubuntu-latest
+    container: pgxn/pgxn-tools
+    strategy:
+      matrix:
+        pg: [14, 15, 16, 17]
+    name: 🐘 Postgres ${{ matrix.pg }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Start PostgreSQL ${{ matrix.pg }}
+        run: pg-start ${{ matrix.pg }}
+      - name: Setup Rust Cache
+        uses: Swatinem/rust-cache@v2
+      - name: Setup Rust
+        uses: dtolnay/rust-toolchain@stable
+      - name: Install pg_partman
+        run: pgxn install pg_partman
+      - name: Test on PostgreSQL ${{ matrix.pg }}
+        run: pgrx-build-test
 
   publish:
     # only publish release events

Cargo.toml

@@ -5,7 +5,7 @@ edition = "2021"
 publish = false
 
 [lib]
-crate-type = ["cdylib"]
+crate-type = ["cdylib", "lib"]
 
 [features]
 default = ["pg17"]

src/bin/pgrx_embed_clerk_fdw.rs

@@ -0,0 +1 @@
+::pgrx::pgrx_embed!();

src/lib.rs

@@ -393,3 +393,37 @@ impl ForeignDataWrapper<ClerkFdwError> for ClerkFdw {
         Ok(())
     }
 }
+
+/// This module is required by `cargo pgrx test` invocations.
+/// It must be visible at the root of your extension crate.
+#[cfg(test)]
+mod pg_test {
+    pub fn setup(_options: Vec<&str>) {
+        // perform one-off initialization when the pg_test framework starts
+    }
+
+    pub fn postgresql_conf_options() -> Vec<&'static str> {
+        // return any postgresql.conf settings that are required for your tests
+        vec![]
+    }
+}
+
+// pgrx tests.
+#[cfg(any(test, feature = "pg_test"))]
+#[pg_schema]
+mod tests {
+    use super::*;
+    #[pg_test]
+    fn create_fdw() {
+        // Just make sure it loads.
+        if let Err(e) = Spi::run(
+            r"
+            CREATE FOREIGN DATA WRAPPER clerk_wrapper
+            HANDLER   clerk_fdw_handler
+            VALIDATOR clerk_fdw_validator
+            ",
+        ) {
+            panic!("CREATE FAILED: {e}");
+        }
+    }
+}