diff --git a/src/librustdoc/doctest.rs b/src/librustdoc/doctest.rs
index 5ce7c49278d23..b45e84aff8cf5 100644
--- a/src/librustdoc/doctest.rs
+++ b/src/librustdoc/doctest.rs
@@ -105,7 +105,7 @@ crate fn run(options: Options) -> Result<(), ErrorReported> {
         registry: rustc_driver::diagnostics_registry(),
     };
 
-    let mut test_args = options.test_args.clone();
+    let test_args = options.test_args.clone();
     let display_warnings = options.display_warnings;
     let nocapture = options.nocapture;
     let externs = options.externs.clone();
@@ -166,12 +166,7 @@ crate fn run(options: Options) -> Result<(), ErrorReported> {
         Err(ErrorReported) => return Err(ErrorReported),
     };
 
-    test_args.insert(0, "rustdoctest".to_string());
-    if nocapture {
-        test_args.push("--nocapture".to_string());
-    }
-
-    test::test_main(&test_args, tests, Some(test::Options::new().display_output(display_warnings)));
+    run_tests(test_args, nocapture, display_warnings, tests);
 
     // Collect and warn about unused externs, but only if we've gotten
     // reports for each doctest
@@ -214,6 +209,19 @@ crate fn run(options: Options) -> Result<(), ErrorReported> {
     Ok(())
 }
 
+crate fn run_tests(
+    mut test_args: Vec<String>,
+    nocapture: bool,
+    display_warnings: bool,
+    tests: Vec<test::TestDescAndFn>,
+) {
+    test_args.insert(0, "rustdoctest".to_string());
+    if nocapture {
+        test_args.push("--nocapture".to_string());
+    }
+    test::test_main(&test_args, tests, Some(test::Options::new().display_output(display_warnings)));
+}
+
 // Look for `#![doc(test(no_crate_inject))]`, used by crates in the std facade.
 fn scrape_test_config(attrs: &[ast::Attribute]) -> TestOptions {
     use rustc_ast_pretty::pprust;
diff --git a/src/librustdoc/markdown.rs b/src/librustdoc/markdown.rs
index 6c8b95c04c9e4..80af2a7aaf5c8 100644
--- a/src/librustdoc/markdown.rs
+++ b/src/librustdoc/markdown.rs
@@ -115,7 +115,7 @@ crate fn render<P: AsRef<Path>>(
 }
 
 /// Runs any tests/code examples in the markdown file `input`.
-crate fn test(mut options: Options) -> Result<(), String> {
+crate fn test(options: Options) -> Result<(), String> {
     let input_str = read_to_string(&options.input)
         .map_err(|err| format!("{}: {}", options.input.display(), err))?;
     let mut opts = TestOptions::default();
@@ -135,14 +135,11 @@ crate fn test(mut options: Options) -> Result<(), String> {
 
     find_testable_code(&input_str, &mut collector, codes, options.enable_per_target_ignores, None);
 
-    options.test_args.insert(0, "rustdoctest".to_string());
-    if options.nocapture {
-        options.test_args.push("--nocapture".to_string());
-    }
-    test::test_main(
-        &options.test_args,
+    crate::doctest::run_tests(
+        options.test_args,
+        options.nocapture,
+        options.display_warnings,
         collector.tests,
-        Some(test::Options::new().display_output(options.display_warnings)),
     );
     Ok(())
 }