Fix digest regex

Signed-off-by: Matej Vasek <mvasek@redhat.com>

docker/pusher.go

@@ -67,7 +67,7 @@ func (n *Pusher) Push(f bosonFunc.Function) (digest string, err error) {
 	return
 }
 
-var digestRE = regexp.MustCompile(`digest:\s+sha256:(?P<Digest>\w{64})`)
+var digestRE = regexp.MustCompile(`digest:\s+(sha256:\w{64})`)
 
 // parseDigest tries to parse the last line from the output, which holds the pushed image digest
 // The output should contain line like this:

docker/pusher_test.go

@@ -0,0 +1,24 @@
+package docker
+
+import "testing"
+
+func Test_parseDigest(t *testing.T) {
+	tests := []struct {
+		name string
+		arg  string
+		want string
+	}{
+		{
+			name: "basic test",
+			arg:  "latest: digest: sha256:a278a91112d17f8bde6b5f802a3317c7c752cf88078dae6f4b5a0784deb81782 size: 2613",
+			want: "sha256:a278a91112d17f8bde6b5f802a3317c7c752cf88078dae6f4b5a0784deb81782",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := parseDigest(tt.arg); got != tt.want {
+				t.Errorf("parseDigest() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}