implement run-pass tests as xtasks

`

xtask/src/build.rs

@@ -0,0 +1,37 @@
+use std::path::PathBuf;
+
+use crate::{command::BuildMode, TestRunError};
+
+pub fn build_hexpath(
+    example: &str,
+    features: Option<&str>,
+    build_mode: BuildMode,
+    build_num: u32,
+) -> anyhow::Result<String> {
+    let features = match features {
+        Some(f) => f,
+        None => "",
+    };
+
+    let filename = format!("{}_{}_{}_{}.hex", example, features, build_mode, build_num);
+    ["ci", "builds", &filename]
+        .iter()
+        .collect::<PathBuf>()
+        .into_os_string()
+        .into_string()
+        .map_err(|e| anyhow::Error::new(TestRunError::PathConversionError(e)))
+}
+
+pub fn compare_builds(file_1: String, file_2: String) -> anyhow::Result<()> {
+    let buf_1 = std::fs::read_to_string(file_1.clone())?;
+    let buf_2 = std::fs::read_to_string(file_2.clone())?;
+
+    if buf_1 != buf_2 {
+        return Err(anyhow::Error::new(TestRunError::FileCmpError {
+            file_1,
+            file_2,
+        }));
+    }
+
+    Ok(())
+}