\documentclass{article}
\usepackage{biblatex}
\usepackage{amsmath}
\addbibresource{biblatex-examples.bib}
\addbibresource{local1.bib}
\addbibresource{~/.vim/bundle/vim-latex/test/completion/local2.bib}
\begin{document}

To test label completion you need to compile the document first!

\begin{equation}
  f(x) = 42
  \label{eq:main-is-working}
\end{equation}

\include{sub1}

\include{"sub2\space with\space spaces"}

\input{"sub3\space with\space spaces"}

\begin{equation}
  \label{eq:test1}
  f(x) = 1
\end{equation}

\begin{equation}
  \label{eq:test2}
  f(x) = 2
\end{equation}

\begin{equation}
  \label{eq:test3}
  f(x) = 3
\end{equation}

\begin{equation}
  \label{eq:test4}
  f(x) = 4
\end{equation}

\begin{equation}
  \label{eq:test5}
  f(x) = 5
\end{equation}

\begin{equation}
  \label{eq:test6}
  f(x) = 6
\end{equation}

\begin{equation}
  \label{eq:test7}
  f(x) = 7
\end{equation}

\begin{equation}
  \label{eq:test8}
  f(x) = 8
\end{equation}

\begin{equation}
  \label{eq:test9}
  f(x) = 9
\end{equation}

\begin{equation}
  \label{eq:test10}
  f(x) = 10
\end{equation}

\begin{subequations}
  \begin{align}
    \label{eq:test11a}
    f(x) &= 11a \\
    \label{eq:test11b}
    f(x) &= 11b
  \end{align}
\end{subequations}

\end{document}
