Add run-make test for rustdoc --emit=dep-info option

tests/run-make/rustdoc-default-output/output-default.stdout

@@ -153,7 +153,7 @@ Options:
         --generate-redirect-map 
                         Generate JSON file at the top level instead of
                         generating HTML redirection files
-        --emit [unversioned-shared-resources,toolchain-shared-resources,invocation-specific]
+        --emit [unversioned-shared-resources,toolchain-shared-resources,invocation-specific,dep-info]
                         Comma separated list of types of output for rustdoc to
                         emit
         --no-run        Compile doctests without running them

tests/run-make/rustdoc-dep-info/bar.rs

@@ -0,0 +1 @@
+include!("foo.rs");

tests/run-make/rustdoc-dep-info/doc.md

@@ -0,0 +1 @@
+blablabla

tests/run-make/rustdoc-dep-info/foo.rs

@@ -0,0 +1 @@
+pub fn foo() {}

tests/run-make/rustdoc-dep-info/lib.rs

@@ -0,0 +1,6 @@
+#![crate_name = "foo"]
+
+#[cfg_attr(doc, doc = include_str!("doc.md"))]
+pub struct Bar;
+
+mod bar;

tests/run-make/rustdoc-dep-info/rmake.rs

@@ -0,0 +1,21 @@
+// This is a simple smoke test for rustdoc's `--emit dep-info` feature. It prints out
+// information about dependencies in a Makefile-compatible format, as a `.d` file.
+
+use run_make_support::assertion_helpers::assert_contains;
+use run_make_support::{path, rfs, rustdoc};
+
+fn main() {
+    // We're only emitting dep info, so we shouldn't be running static analysis to
+    // figure out that this program is erroneous.
+    rustdoc().input("lib.rs").arg("-Zunstable-options").emit("dep-info").run();
+
+    let content = rfs::read_to_string("foo.d");
+    assert_contains(&content, "lib.rs:");
+    assert_contains(&content, "foo.rs:");
+    assert_contains(&content, "bar.rs:");
+    assert_contains(&content, "doc.md:");
+
+    // Now we check that we can provide a file name to the `dep-info` argument.
+    rustdoc().input("lib.rs").arg("-Zunstable-options").emit("dep-info=bla.d").run();
+    assert!(path("bla.d").exists());
+}