Test code example in readme

Author: frigus02

Cargo.toml

@@ -48,6 +48,7 @@ ureq = { version = "2", optional = true }
 [dev-dependencies]
 async-std = { version = "1.9.0", features = ["attributes"] }
 backtrace = "0.3.60"
+doc-comment = "0.3.3"
 env_logger = "0.9.0"
 opentelemetry = { version = "0.16", features = ["rt-tokio"] }
 opentelemetry-application-insights = { path = ".", features = ["reqwest-client", "reqwest-blocking-client"] }

README.md

@@ -12,7 +12,7 @@ An [Azure Application Insights](https://docs.microsoft.com/en-us/azure/azure-mon
 
 Configure a OpenTelemetry pipeline using the Application Insights exporter and start creating spans (this example requires the **reqwest-client** feature):
 
-```rust
+```rust,no_run
 use opentelemetry::trace::Tracer as _;
 
 fn main() {

src/lib.rs

@@ -218,6 +218,8 @@ mod convert;
 #[cfg(feature = "metrics")]
 mod metrics;
 mod models;
+#[cfg(doctest)]
+mod readme_test;
 mod tags;
 mod trace;
 mod uploader;

src/readme_test.rs

@@ -0,0 +1 @@
+doc_comment::doctest!("../README.md");