public void HashForNthCommit()
{
var output = Helpers.LoadResource(Paths.GitSingleCommitOutput, typeof(GitCommandsTest).Assembly);
var executorMock = new Mock <ICommandLineExecutor>();
const string repoPath = "dir";
const int nthCommit = 5;
const int allCommits = 123;
const string commitCountCommand = "rev-list --count HEAD";
var nthCommitHashCommand = $"log -1 HEAD~{allCommits - nthCommit + 1}";
executorMock
.Setup(mock => mock.Execute("git", It.Is <string>(command => command == commitCountCommand), repoPath))
.Returns(new[] { allCommits.ToString() });
executorMock
.Setup(mock => mock.Execute("git", It.Is <string>(command => command == nthCommitHashCommand), repoPath))
.Returns(output.Split('\n'));
var gitCommands = new GitCommands(executorMock.Object);
var result = gitCommands.GetHashForNthCommit(repoPath, nthCommit);
executorMock.Verify(mock => mock.Execute("git", commitCountCommand, repoPath), Times.Once);
executorMock.Verify(mock => mock.Execute("git", nthCommitHashCommand, repoPath), Times.Once);
result.Should()
.Be("abb3cc3d7e405c39eae91b22c41d1281b9075cd4");
}