fix: build docker image even if the dockerfile hasn't changed

* Update README to showcase how to write tests using the macro instead
* Update README to note about the ws:// prefix.
* Update github actions to use the rust action instead of setting the
  stable toolchain manually, and use `DOCKER_BUILD` flag at least once
  before the tests.

Author: stonecharioteer

.github/workflows/tests.yml

@@ -8,14 +8,18 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v1
-    - name: Install stable
-      run: rustup toolchain install stable
     - name: Install protoc
-      run: sudo apt-get install protobuf-compiler
+      run: sudo apt-get update -qqq && sudo apt-get install -y protobuf-compiler
+    - name: Install latest nightly
+      uses: actions-rs/toolchain@v1
+      with:
+          toolchain: stable
+          override: true
+          components: rustfmt, clippy
     - name: Build
-      run: cargo build --all
+      run: DOCKER_BUILD=1 cargo build --all
     - name: Run tests
-      run: DOCKER_BUILD=1 cargo test
+      run: DOCKER_BUILD=1 cargo test -- --test-threads=1
 
 
   fmt:

README.md

@@ -30,22 +30,21 @@ snippet.
 ```rust
 #[cfg(test)]
 mod test {
-    use testcontainers::clients;
-    use testcontainers::core::WaitFor;
-    use testcontainers::images::generic::GenericImage;
+    use crate::new_nym_client;
     #[tokio::test]
     async fn test_with_nym() {
-        let docker_client = clients::Cli::default();
-        let nym_ready_message = WaitFor::message_on_stderr("Client startup finished!");
-        let nym_dialer_image = GenericImage::new("nym", "latest")
-            .with_env_var("NYM_ID", "test_connection_dialer")
-            .with_wait_for(nym_ready_message.clone())
-            .with_exposed_port(1977);
-        let dialer_container = docker_client.run(nym_dialer_image);
-        let dialer_port = dialer_container.get_host_port_ipv4(1977);
-        let dialer_uri = format!("ws://0.0.0.0:{dialer_port}");
+
+        let nym_id = "test_transport_connection_dialer";
+        #[allow(unused)]
+        let dialer_uri: String;
+        new_nym_client!(nym_id, dialer_uri);
+        todo!("Now you can use the dialer_uri to make requests.")
     }
 }
 ```
 
 One can create as many of these as needed, limited only by the server resources.
+
+**NOTE**: When using a URI for connections, ensure that you're prefixing the
+URI with the `ws://` protocol type, otherwise the nym client assumes http and
+crashes unceremoniously.

build.rs

@@ -1,9 +1,8 @@
 use std::env;
 use std::process::Command;
+
 fn main() {
-    println!("cargo:rerun-if-changed=Dockerfile.nym");
-    let docker_build = env::var("DOCKER_BUILD").is_ok();
-    if docker_build {
+    if env::var("DOCKER_BUILD").is_ok() {
         let output = Command::new("docker")
             .arg("build")
             .arg("-t")