Ensure temp download file is rewinded before reading it (#23)

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name    = "terve"
-version = "0.5.0"
+version = "0.5.1"
 edition = "2018"
 
 [dependencies]

src/terragrunt.rs

@@ -1,4 +1,8 @@
-use std::{error::Error, fs::File, io::copy};
+use std::{
+    error::Error,
+    fs::File,
+    io::{copy, Seek, SeekFrom},
+};
 
 use crate::{
     http::HttpClient,
@@ -37,6 +41,7 @@ pub fn install_binary_version(
                 return Err(other.into());
             }
         }
+        tmp_file.seek(SeekFrom::Start(0))?;
         let mut opt_file = File::create(&opt_file_path)?;
         copy(&mut tmp_file, &mut opt_file)?;
         #[cfg(unix)]

src/utils.rs

@@ -22,7 +22,6 @@ pub fn check_sha256_sum(mut file: &File, expected_sha256: &str) -> Result<(), Bo
         )
         .into());
     }
-    file.seek(SeekFrom::Start(0))?;
     Ok(())
 }
 

tests/main.rs

@@ -14,6 +14,7 @@ fn test_workflows() {
     };
     test_terraform_all(&home_dir);
     test_terragrunt_all(&home_dir);
+    test_install_old_terragrunt_with_no_shasums(&home_dir);
 }
 
 fn test_terraform_all(home_dir: &PathBuf) {
@@ -218,6 +219,44 @@ fn test_terragrunt_all(home_dir: &PathBuf) {
         .stdout(predicate::str::is_empty());
 }
 
+// See https://github.com/superblk/terve/issues/21
+fn test_install_old_terragrunt_with_no_shasums(home_dir: &PathBuf) {
+    terve()
+        .arg("i")
+        .arg("tg")
+        .arg("0.18.0")
+        .assert()
+        .success()
+        .code(0)
+        .stderr(predicate::str::contains(
+            "WARNING: Skipping SHA256 file integrity check",
+        ))
+        .stdout(predicate::str::contains("Installed terragrunt 0.18.0"));
+
+    let opt_file_path = if cfg!(unix) {
+        home_dir
+            .join(".terve")
+            .join("opt")
+            .join("terragrunt")
+            .join("0.18.0")
+    } else {
+        home_dir
+            .join(".terve")
+            .join("opt")
+            .join("terragrunt.exe")
+            .join("0.18.0")
+    };
+
+    assert!(opt_file_path.metadata().unwrap().len() > 0);
+
+    Command::new(opt_file_path)
+        .arg("--version")
+        .assert()
+        .success()
+        .code(0)
+        .stdout(predicate::str::contains("0.18.0"));
+}
+
 fn terve() -> Command {
     Command::cargo_bin("terve").unwrap()
 }