Skip conformance tests that require Docker when Docker is not installed

Signed-off-by: Ryan Levick <[email protected]>

Author: rylev

tests/conformance-tests/src/lib.rs

@@ -15,8 +15,22 @@ pub fn run_test(
             conformance_tests::config::Precondition::TcpEcho => {
                 services.push("tcp-echo");
             }
-            conformance_tests::config::Precondition::Redis => services.push("redis"),
-            conformance_tests::config::Precondition::Mqtt => services.push("mqtt"),
+            conformance_tests::config::Precondition::Redis => {
+                if is_docker_installed() {
+                    services.push("redis")
+                } else {
+                    // Skip the test if docker is not installed.
+                    return Ok(());
+                }
+            }
+            conformance_tests::config::Precondition::Mqtt => {
+                if is_docker_installed() {
+                    services.push("mqtt")
+                } else {
+                    // Skip the test if docker is not installed.
+                    return Ok(());
+                }
+            }
             conformance_tests::config::Precondition::KeyValueStore(_) => {}
             conformance_tests::config::Precondition::Sqlite => {}
         }
@@ -57,3 +71,12 @@ pub fn run_test(
     }
     Ok(())
 }
+
+/// Whether or not docker is installed on the system.
+fn is_docker_installed() -> bool {
+    std::process::Command::new("docker")
+        .arg("--version")
+        .output()
+        .map(|output| output.status.success())
+        .unwrap_or(false)
+}