chore(deps): remove spectral from dev-dependencies (#526)

`spectral` is outdated (last update >7 years ago), it causes warning:

```
the following packages contain code that will be rejected by a future version of Rust: rustc-serialize v0.3.24
```

And actually there is no need in it

testcontainers/Cargo.toml

@@ -34,6 +34,5 @@ experimental = [ "async-trait", "bollard", "tokio" ]
 [dev-dependencies]
 pretty_env_logger = "0.5"
 reqwest = { version = "0.11.14", features = [ "blocking" ] }
-spectral = "0.6.0"
 testimages = { path = "../testimages" }
 tokio = { version = "1", features = [ "macros" ] }

testcontainers/src/clients/cli.rs

@@ -473,7 +473,6 @@ impl Drop for Client {
 mod tests {
     use super::*;
     use crate::{core::WaitFor, images::generic::GenericImage, Image};
-    use spectral::prelude::*;
     use std::collections::BTreeMap;
 
     #[derive(Default)]
@@ -702,7 +701,14 @@ mod tests {
         docker.stdout_logs(container.id());
         let after_logs = Instant::now();
 
-        assert_that(&(after_run - before_run)).is_greater_than(Duration::from_secs(1));
-        assert_that(&(after_logs - before_logs)).is_less_than(Duration::from_secs(1));
+        const ONE_SEC: Duration = Duration::from_secs(1);
+        assert!(
+            (after_run - before_run) > ONE_SEC,
+            "run completed in less than a second"
+        );
+        assert!(
+            (after_logs - before_logs) < ONE_SEC,
+            "log fetching took more than a second"
+        );
     }
 }

testcontainers/src/clients/http.rs

@@ -351,7 +351,6 @@ impl DockerAsync for Http {
 mod tests {
     use super::*;
     use crate::images::generic::GenericImage;
-    use spectral::prelude::*;
 
     async fn inspect(client: &bollard::Docker, id: &str) -> ContainerInspectResponse {
         client.inspect_container(id, None).await.unwrap()
@@ -365,8 +364,12 @@ mod tests {
 
         // inspect volume and env
         let container_details = inspect(&docker.inner.bollard, container.id()).await;
-        assert_that!(container_details.host_config.unwrap().publish_all_ports)
-            .is_equal_to(Some(true));
+        let publish_ports = container_details
+            .host_config
+            .unwrap()
+            .publish_all_ports
+            .unwrap();
+        assert_eq!(publish_ports, true, "publish_all_ports must be `true`");
     }
 
     #[tokio::test(flavor = "multi_thread")]
@@ -385,8 +388,8 @@ mod tests {
             .unwrap()
             .port_bindings
             .unwrap();
-        assert_that!(&port_bindings).contains_key(&"456/tcp".into());
-        assert_that!(&port_bindings).contains_key(&"888/tcp".into());
+        assert!(port_bindings.contains_key("456/tcp"));
+        assert!(port_bindings.contains_key("888/tcp"));
     }
 
     #[tokio::test(flavor = "multi_thread")]
@@ -417,7 +420,8 @@ mod tests {
         let container = docker.run(image).await;
 
         let container_details = inspect(&docker.inner.bollard, container.id()).await;
-        assert_that!(container_details.name.unwrap()).ends_with("hello_container");
+        let container_name = container_details.name.unwrap();
+        assert!(container_name.ends_with("hello_container"));
     }
 
     #[tokio::test(flavor = "multi_thread")]