Add git-describe support

Includes 'git_describe_commit' and 'git_describe_workdir'.

1 files changed, 106 insertions, 0 deletions

diff --git a/describe_test.go b/describe_test.go
new file mode 100644
index 0000000..25af107
--- /dev/null
+++ b/describe_test.go
@@ -0,0 +1,106 @@
+package git
+
+import (
+	"path"
+	"runtime"
+	"strings"
+	"testing"
+)
+
+func TestDescribeCommit(t *testing.T) {
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	describeOpts, err := DefaultDescribeOptions()
+	checkFatal(t, err)
+
+	formatOpts, err := DefaultDescribeFormatOptions()
+	checkFatal(t, err)
+
+	commitID, _ := seedTestRepo(t, repo)
+
+	commit, err := repo.LookupCommit(commitID)
+	checkFatal(t, err)
+
+	// No annotated tags can be used to describe master
+	_, err = commit.Describe(&describeOpts)
+	checkDescribeNoRefsFound(t, err)
+
+	// Fallback
+	fallback := describeOpts
+	fallback.ShowCommitOidAsFallback = true
+	result, err := commit.Describe(&fallback)
+	checkFatal(t, err)
+	resultStr, err := result.Format(&formatOpts)
+	checkFatal(t, err)
+	compareStrings(t, "473bf77", resultStr)
+
+	// Abbreviated
+	abbreviated := formatOpts
+	abbreviated.AbbreviatedSize = 2
+	result, err = commit.Describe(&fallback)
+	checkFatal(t, err)
+	resultStr, err = result.Format(&abbreviated)
+	checkFatal(t, err)
+	compareStrings(t, "473b", resultStr)
+
+	createTestTag(t, repo, commit)
+
+	// Exact tag
+	patternOpts := describeOpts
+	patternOpts.Pattern = "v[0-9]*"
+	result, err = commit.Describe(&patternOpts)
+	checkFatal(t, err)
+	resultStr, err = result.Format(&formatOpts)
+	checkFatal(t, err)
+	compareStrings(t, "v0.0.0", resultStr)
+
+	// Pattern no match
+	patternOpts.Pattern = "v[1-9]*"
+	result, err = commit.Describe(&patternOpts)
+	checkDescribeNoRefsFound(t, err)
+
+	commitID, _ = updateReadme(t, repo, "update1")
+	commit, err = repo.LookupCommit(commitID)
+	checkFatal(t, err)
+
+	// Tag-1
+	result, err = commit.Describe(&describeOpts)
+	checkFatal(t, err)
+	resultStr, err = result.Format(&formatOpts)
+	checkFatal(t, err)
+	compareStrings(t, "v0.0.0-1-gd88ef8d", resultStr)
+
+	// Strategy: All
+	describeOpts.Strategy = DescribeAll
+	result, err = commit.Describe(&describeOpts)
+	checkFatal(t, err)
+	resultStr, err = result.Format(&formatOpts)
+	checkFatal(t, err)
+	compareStrings(t, "heads/master", resultStr)
+
+	repo.CreateBranch("hotfix", commit, false)
+
+	// Workdir (branch)
+	result, err = repo.DescribeWorkdir(&describeOpts)
+	checkFatal(t, err)
+	resultStr, err = result.Format(&formatOpts)
+	checkFatal(t, err)
+	compareStrings(t, "heads/hotfix", resultStr)
+}
+
+func checkDescribeNoRefsFound(t *testing.T, err error) {
+	// The failure happens at wherever we were called, not here
+	_, file, line, ok := runtime.Caller(1)
+	if !ok {
+		t.Fatalf("Unable to get caller")
+	}
+	if err == nil || !strings.Contains(err.Error(), "No reference found, cannot describe anything") {
+		t.Fatalf(
+			"%s:%v: was expecting error 'No reference found, cannot describe anything', got %v",
+			path.Base(file),
+			line,
+			err,
+		)
+	}
+}