fs: Fix parsing of paths under Windows - fixes #2353

Before this copyto would parse windows paths incorrectly.

This change moves the parsing code into fspath and makes sure
fspath.Split calls fspath.Parse which does the parsing correctly for

This also renames fspath.RemoteParse to fspath.Parse for consistency

fs/fspath/path_test.go

@@ -7,8 +7,23 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestRemoteSplit(t *testing.T) {
+func TestParse(t *testing.T) {
+	for _, test := range []struct {
+		in, wantConfigName, wantFsPath string
+	}{
+		{"", "", ""},
+		{"/path/to/file", "", "/path/to/file"},
+		{"path/to/file", "", "path/to/file"},
+		{"remote:path/to/file", "remote", "path/to/file"},
+		{"remote:/path/to/file", "remote", "/path/to/file"},
+	} {
+		gotConfigName, gotFsPath := Parse(test.in)
+		assert.Equal(t, test.wantConfigName, gotConfigName)
+		assert.Equal(t, test.wantFsPath, gotFsPath)
+	}
+}
 
+func TestSplit(t *testing.T) {
 	for _, test := range []struct {
 		remote, wantParent, wantLeaf string
 	}{
@@ -27,7 +42,7 @@ func TestRemoteSplit(t *testing.T) {
 		{"root/", "root/", ""},
 		{"a/b/", "a/b/", ""},
 	} {
-		gotParent, gotLeaf := RemoteSplit(test.remote)
+		gotParent, gotLeaf := Split(test.remote)
 		assert.Equal(t, test.wantParent, gotParent, test.remote)
 		assert.Equal(t, test.wantLeaf, gotLeaf, test.remote)
 		assert.Equal(t, test.remote, gotParent+gotLeaf, fmt.Sprintf("%s: %q + %q != %q", test.remote, gotParent, gotLeaf, test.remote))