Test for checkout_head (#39034)

* Test for checkout_head

* Remember to actually close the file

* And actually force the checkout

Author: kshyatt

stdlib/LibGit2/test/libgit2.jl

@@ -1726,6 +1726,19 @@ mktempdir() do dir
         end
     end
 
+    @testset "checkout_head" begin
+        LibGit2.with(LibGit2.GitRepo(cache_repo)) do repo
+            # modify file
+            repo_file = open(joinpath(cache_repo,test_file), "a")
+            println(repo_file, commit_msg1 * randstring(10))
+            close(repo_file)
+            # and checkout HEAD once more
+            LibGit2.checkout_head(repo, options=LibGit2.CheckoutOptions(checkout_strategy=LibGit2.Consts.CHECKOUT_FORCE))
+            @test LibGit2.headname(repo) == master_branch
+            @test !LibGit2.isdirty(repo)
+        end
+    end
+
     @testset "checkout/headname" begin
         LibGit2.with(LibGit2.GitRepo(cache_repo)) do repo
             LibGit2.checkout!(repo, string(commit_oid1))
@@ -1734,7 +1747,6 @@ mktempdir() do dir
         end
     end
 
-
     if Sys.isunix()
         @testset "checkout/proptest" begin
             LibGit2.with(LibGit2.GitRepo(test_repo)) do repo