diff --git a/.Rbuildignore b/.Rbuildignore
index 3e82400..58566c0 100644
--- a/.Rbuildignore
+++ b/.Rbuildignore
@@ -17,3 +17,4 @@ demo/gexfplot\.R
 ^README-.*\.png$
 ^\.travis\.yml$
 ^appveyor\.yml$
+^codecov\.yml$
diff --git a/ChangeLog b/ChangeLog
index 86fbf97..d1e8a4d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2016-11-10  George G. Vega Yon <g.vegayon@gmail.com>
+	* R/bugs.r: Creating a more generic method for checking viz attrs.
+	* R/rgexf.r: Started moving from write.gexf to gexf. In the 2.0
+	  version write.gexf should be for exporting gexf graphs only.
+	* demo/*.R: Replaced write.gexf with gexf.
+
 2016-11-09  George G. Vega Yon <g.vegayon@gmail.com>
 	* Added ChangeLog
 	* Change Depends to Imports and added namespace calls
diff --git a/DESCRIPTION b/DESCRIPTION
index a1f625d..03f4141 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -26,5 +26,7 @@ License: MIT + file LICENSE
 LazyLoad: yes
 RoxygenNote: 5.0.1
 Suggests: knitr,
-    rmarkdown
+    rmarkdown,
+    testthat,
+    covr
 VignetteBuilder: knitr
diff --git a/NAMESPACE b/NAMESPACE
index e9f8e94..8502f0c 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -10,6 +10,7 @@ export(add.node.spell)
 export(check.dpl.edges)
 export(checkTimes)
 export(edge.list)
+export(gexf)
 export(gexf.to.igraph)
 export(igraph.to.gexf)
 export(new.gexf.graph)
diff --git a/R/bugs.r b/R/bugs.r
index 8ff42d5..79109cc 100644
--- a/R/bugs.r
+++ b/R/bugs.r
@@ -48,58 +48,49 @@ checkTimes <- function(x, format='date') {
 #checkTimes(test, format='dateTime')
 #checkTimes('2012-02-01T00:00:00', 'dateTime')
 
-.parseNodesVizAtt <- function(nodesVizAtt, nodes) {
-################################################################################
-# Parses nodes viz attributes checking dimentions, classes and names
-################################################################################
-  if (any(lapply(nodesVizAtt, length) > 0)) {
-    supportedNodesVizAtt <- c("color", "position", "size", "shape", "image")
-    if (all(names(nodesVizAtt) %in% supportedNodesVizAtt)) {
-      if (all(lapply(nodesVizAtt, NROW) == NROW(nodes))) {
-        return(length(nodesVizAtt))
-      }
-      else {
-        nodesVizAtt <- lapply(nodesVizAtt, NROW)
-        nodesVizAtt <- nodesVizAtt[nodesVizAtt != NROW(nodes)]
-        stop("Insuficient number of \"nodeVizAtt\" rows: The atts ",
-             paste(names(nodesVizAtt), unlist(nodesVizAtt), sep=" (", collapse=" rows), "),")\n",
-             "Every att should have the same number of rows than nodes there are (",NROW(nodes),")")
-      }
-    }
-    else {
-      noviz <- names(nodesVizAtt)
-      noviz <- noviz[!(noviz %in% supportedNodesVizAtt)]
-      stop("Invalid \"nodeVizAtt\": ",noviz,"\nOnly \"color\", \"position\", \"size\", \"shape\" and \"image\" are supported")
-    }
-  }
-  else return(0)
-}
+vizAttsSpecs <- list(
+  color = function(x) {
+    if (is.vector(x) || ncol(x) == 1) {
+      warning("Trying to coerce colors into RGBA")
+      return( cbind(t(col2rgb(x)), 1) )
+    } else if (ncol(x) != 4) # Must be 4-columns
+      stop("the color attribute must have 4 columns (RGBA).")
+    
+    # Must have the right range
+    if (max(x[,-4]) > 255 || min(x[,-4]) < 0) 
+      stop("The RGB colors must be in the range [0,255].")
+    
+    if (max(x[,4]) > 1 | min(x[,4]) < 0)
+      stop("The alpha part of the colors (4th column) must be within [0,1].")
+    
+    return(x)
+    
+  },
+  position = function(x) x,
+  size = function(x) x, 
+  shape = function(x) x,
+  image = function(x) x
+)
 
-.parseEdgesVizAtt <- function(edgesVizAtt, edges) {
-################################################################################
-# Parses edges viz attributes checking dimentions, classes and names
-################################################################################
-  if (any(lapply(edgesVizAtt, length) > 0)) {
-    supportedEdgeVizAtt <- c("color", "size", "shape")
-    if (all(names(edgesVizAtt) %in% supportedEdgeVizAtt)) {
-      if (all(lapply(edgesVizAtt, NROW) == NROW(edges))) {
-        return(length(edgesVizAtt))
-      }
-      else {
-        edgesVizAtt <- lapply(edgesVizAtt, NROW)
-        edgesVizAtt <- edgesVizAtt[edgesVizAtt != NROW(edges)]
-        stop("Insuficient number of \"edgeVizAtt\" rows: The atts ",
-             paste(names(edgesVizAtt), unlist(edgesVizAtt), sep=" (", collapse=" rows), "),")\n",
-             "Every att should have the same number of rows than edges there are (",NROW(edges),")")
-      }
-    }
-    else {
-      noviz <- names(edgesVizAtt)
-      noviz <- noviz[!(noviz %in% supportedEdgeVizAtt)]
-      stop("Invalid \"edgesVizAtt\": ",noviz,"\nOnly \"color\", \"size\" and \"shape\" are supported")
-    }
-  }
-  else return(0)
+parseVizAtt <- function(att, dat, n, type=c("nodes", "edges")) {
+  # Generic checks
+  if (is.vector(dat)) {
+    if (length(dat) < n)
+      stop("The attribute -",att,"- has incorrect length (has ",length(dat),
+           ", and must have ",n,").")
+  } else if (inherits(dat, c("data.frame", "matrix"))) {
+    if (nrow(dat) != n)
+      stop("The attribute -",att,"- has incorrect number of rows (has ",
+           nrow(dat)," and it must have ",n,").")
+  } else stop("The attribute -",att,"- of class -",class(dat),"- is not supported.")
+  
+  # What list of attrs
+  checks <- if (type=="nodes") c("color", "position", "size", "shape", "image")
+  else if (type=="edges") c("color", "size", "shape")
+  
+  if (att %in% checks) vizAttsSpecs[[att]](dat)
+  else stop("The attribute -", att,"- is not supported for -", type,"-. Only '",
+            paste(checks, collapse="', '"), " are currently supported.") 
 }
 
 .parseEdgesWeight <- function(edgesWeight, edges) {
diff --git a/R/rgexf-package.r b/R/rgexf-package.r
index d5ed156..dcce025 100644
--- a/R/rgexf-package.r
+++ b/R/rgexf-package.r
@@ -108,7 +108,7 @@ NULL
 #'                         target=c(4,2,3,3,4,2,4,1,1))
 #'     
 #'     # Building gexf graph
-#'     mygraph <- write.gexf(nodes=people, edges=relations)
+#'     mygraph <- gexf(nodes=people, edges=relations)
 #'     
 #'     # Summary and pring
 #'     summary(mygraph)
@@ -148,7 +148,7 @@ NULL
 #' 
 #' 
 #' @name rgexf-package
-#' @aliases rgexf-package rgexf gexf gephi
+#' @aliases rgexf-package rgexf gephi
 #' @docType package
 #' @note See the GEXF primer for details on the GEXF graph format:
 #' \url{https://gephi.org/gexf/1.2draft/gexf-12draft-primer.pdf}
diff --git a/R/rgexf.r b/R/rgexf.r
index 6b1d7b0..b2da609 100644
--- a/R/rgexf.r
+++ b/R/rgexf.r
@@ -29,26 +29,23 @@ edge.list <- function(x) {
 # Translate a edgelist to two objects list (nodes + edges)
 ################################################################################
   objClass <- class(x)
-  nEdges <- NROW(x)
-  nCols <- NCOL(x) == 2
+  k        <- ncol(x) == 2
   
-  if (objClass %in% c("matrix", "data.frame")) {
+  if (any(c("matrix", "data.frame") %in% objClass)) {
     
-    if (nCols) {
+    if (k == 2) {
       # If it is not a factor
       if (!is.factor(x)) x <- factor(c(x[,1], x[,2]))
       edges <- matrix(unclass(x), byrow=FALSE, ncol=2)
       colnames(edges) <- c("source","target")
-      nodes <- data.frame(id=1:nlevels(x), label=levels(x), stringsAsFactors=F)
+      nodes <- data.frame(id=1:nlevels(x), label=levels(x), stringsAsFactors=FALSE)
       
-      edgelist <- list(nodes=nodes, edges=edges)
-      
-      return(edgelist)
+      return(list(nodes=nodes, edges=edges))
     }
-    else stop("Insuficcient number of columns (", nCols,")")
+    else stop("Insufficient number of columns (", k,")")
   }
-  else stop(objClass, 
-                  " class not allowed, try with a \"matrix\" or a \"data.frame\"")
+  else stop("-", objClass, 
+                  "- class not supported, try with a \"matrix\" or a \"data.frame\"")
 }
 
 .defAtt <- function(x, parent) {
@@ -71,7 +68,7 @@ edge.list <- function(x) {
     )
 
   for (i in attvec) 
-    tmpdoc <- c(tmpdoc, .writeXMLLine("attvalue", tmpatt[i, ]) , sep="") 
+    tmpdoc <- c(tmpdoc, .writeXMLLine("attvalue", tmpatt[i,,drop=FALSE ]) , sep="") 
 
   paste(c("<attvalues>", tmpdoc, "</attvalues>"), sep="", collapse="")
 }
@@ -151,7 +148,7 @@ edge.list <- function(x) {
   # Loop if there are not any attributes
   if (!attributes && !vizattributes) {
     for (i in vec) {
-      XML::parseXMLAndAdd(.writeXMLLine(type, datasetnoatt[i,]),parent=PAR)
+      XML::parseXMLAndAdd(.writeXMLLine(type, datasetnoatt[i,,drop=FALSE]),parent=PAR)
     }
     return(NULL)
   }
@@ -162,7 +159,7 @@ edge.list <- function(x) {
     for (i in vec) {      
       # Adding directly
       XML::parseXMLAndAdd(
-        paste(.writeXMLLine(type, datasetnoatt[i,], finalizer=FALSE), 
+        paste(.writeXMLLine(type, datasetnoatt[i,,drop=FALSE], finalizer=FALSE), 
               .addAtts(att[i,], attvec), # Builds atts definition
               "</",type,">",sep=""),
         parent=PAR)
@@ -175,20 +172,20 @@ edge.list <- function(x) {
     # Node/Edge + Atts 
     if (attributes) {
       tempnode0 <- paste(
-        .writeXMLLine(type, datasetnoatt[i,], finalizer=FALSE),
+        .writeXMLLine(type, datasetnoatt[i,,drop=FALSE], finalizer=FALSE),
         .addAtts(att[i,], attvec), sep="")
     }
-    else tempnode0 <- .writeXMLLine(type, datasetnoatt[i,], finalizer=FALSE)
+    else tempnode0 <- .writeXMLLine(type, datasetnoatt[i,,drop=FALSE], finalizer=FALSE)
     
     # Viz Att printing
     # Colors
     if (vizcolors) {
-      tempnode0 <- paste(tempnode0, .writeXMLLine("color", vizcol.df[i,]),
+      tempnode0 <- paste(tempnode0, .writeXMLLine("color", vizcol.df[i,,drop=FALSE]),
                          sep="")
     }
     # Position
     if (vizposition) {
-      tempnode0 <- paste(tempnode0, .writeXMLLine("position", vizpos.df[i,]),
+      tempnode0 <- paste(tempnode0, .writeXMLLine("position", vizpos.df[i,,drop=FALSE]),
                          sep="")
     }
     # Size
@@ -203,7 +200,7 @@ edge.list <- function(x) {
     }
     # Image
     if (vizimage) {
-      tempnode0 <- paste(tempnode0, .writeXMLLine("shape", vizimg.df[i,]),
+      tempnode0 <- paste(tempnode0, .writeXMLLine("shape", vizimg.df[i,,drop=FALSE]),
                          sep="")
     }
     XML::parseXMLAndAdd(sprintf("%s</%s>",tempnode0, type), parent=PAR)
@@ -213,12 +210,13 @@ edge.list <- function(x) {
 
 
 
-#' Builds a graph of \code{gexf} class
+#' Creates an object of class \code{gexf}
 #' 
-#' \code{write.gexf} takes a \code{node} matrix (or dataframe) and an
+#' Takes a \code{node} matrix (or dataframe) and an
 #' \code{edge} matrix (or dataframe) and creates a \code{gexf} object
 #' containing a data-frame representation and a gexf representation of a graph.
 #' 
+#' @details
 #' Just like \code{nodesVizAtt} and \code{edgesVizAtt}, \code{nodesAtt} and
 #' \code{edgesAtt} must have the same number of rows as nodes and edges,
 #' respectively. Using data frames is necessary as in this way data types are
@@ -286,6 +284,7 @@ edge.list <- function(x) {
 #' @param encoding Encoding of the graph.
 #' @param vers Character scalar. Version of the GEXF format to generate.
 #' By default \code{"1.3"}.
+#' @param ... Passed to \code{gexf}.
 #' @return A \code{gexf} class object (list). Contains the following: \itemize{
 #' \item \code{meta} : (list) Meta data describing the graph.  \item
 #' \code{mode} : (list) Sets the default edge type and the graph mode.  \item
@@ -317,8 +316,12 @@ edge.list <- function(x) {
 #'   demo(gexfbuildfromscratch) # Example building a net from scratch.
 #'   }
 #' 
+#' @name gexf-class
+NULL
+
 #' @export
-write.gexf <- function(
+#' @rdname gexf-class
+gexf <- function(
   ################################################################################  
   # Prints the gexf file
   ################################################################################
@@ -346,21 +349,23 @@ write.gexf <- function(
   ##############################################################################
   # CLASS CHECKS AND OTHERS CHECKS
   
-  # version
-  vers <- gexf_version(vers)
-  
   # Nodes
-  if (is.data.frame(nodes) | is.matrix(nodes)) {
+  if (inherits(nodes, c("data.frame", "matrix"))) {
     if (NCOL(nodes) != 2) stop("-nodes- should have two columns not ", NCOL(nodes))
   }
   else stop("Invalid object type: -nodes- should be a two column data.frame or a matrix")
   
   # Edges
-  if (is.data.frame(edges) | is.matrix(edges)) {
+  if (inherits(edges, c("data.frame", "matrix"))) {
     if (NCOL(edges) != 2) stop("-edges- should have two columns not ", NCOL(edges))
   }
   else stop("Invalid object type: -edges- should be a two column data.frame or a matrix")
   
+  # version
+  vers <- gexf_version(vers)
+  n <- nrow(nodes)
+  m <- nrow(edges)
+  
   # Edges Label
   .parseEdgesLabel(edgesLabel, edges)
   
@@ -374,13 +379,24 @@ write.gexf <- function(
   .parseEdgesWeight(edgesWeight, edges)
   
   # Parsing edges Viz Att
-  nEdgesVizAtt <- .parseEdgesVizAtt(edgesVizAtt, edges)
+  edgesVizAtt  <- if (length(unlist(edgesVizAtt))) {
+    Map(function(a, b) parseVizAtt(a, b, m, "edges"), a=names(edgesVizAtt),
+        b=edgesVizAtt)
+  } else NULL
+  
+  nEdgesVizAtt <- length(edgesVizAtt)
+  # nEdgesVizAtt <- .parseEdgesVizAtt(edgesVizAtt, edges)
   
   # Nodes Att
   nNodesAtt <- .parseNodesAtt(nodesAtt, nodes)
   
   # Parsing nodes Viz Atts
-  nNodesVizAtt <- .parseNodesVizAtt(nodesVizAtt, nodes)
+  nodesVizAtt  <- if (length(unlist(nodesVizAtt))) {
+    Map(function(a, b) parseVizAtt(a, b, n, "nodes"), a=names(nodesVizAtt),
+                        b=nodesVizAtt)
+  } else NULL
+  
+  nNodesVizAtt <- length(nodesVizAtt)
   
   # Checking the number of digits
   if (!is.integer(digits)) stop("Invalid number of digits ",digits,
@@ -393,14 +409,16 @@ write.gexf <- function(
   if (length(nodeDynamic) > 0) {
     if (is.data.frame(nodeDynamic) | is.matrix(nodeDynamic)) {
       if (NROW(nodeDynamic) == NROW(nodes)) dynamic[1] <- TRUE
-      else stop("Insuficient number of rows: -nodeDynamic- (",NROW(nodeDynamic), " rows) should have the same number of rows than nodes there are (", NROW(nodes),")")
+      else stop("Insufficient number of rows: -nodeDynamic- (",NROW(nodeDynamic), 
+                " rows) should have the same number of rows than nodes there are (",
+                NROW(nodes),")")
     } else stop("Invalid object type: -nodeDynamic- should be a two columns data.frame or a matrix")
   }
   
   if (length(edgeDynamic) > 0) {
     if (is.data.frame(edgeDynamic) | is.matrix(edgeDynamic)) {
       if (NROW(edgeDynamic) == NROW(edges)) dynamic[2] <- TRUE
-      else stop("Insuficient number of rows: -edgeDynamic- (",NROW(edgeDynamic), " rows) should have the same number of rows than edges there are (", NROW(edges),")")
+      else stop("Insufficient number of rows: -edgeDynamic- (",NROW(edgeDynamic), " rows) should have the same number of rows than edges there are (", NROW(edges),")")
     } else stop("Invalid object type: -edgeDynamic- should be a two columns data.frame or a matrix")
   }
   
@@ -702,8 +720,8 @@ write.gexf <- function(
     atts.definitions=list(nodes = nodesAttDf, edges = edgesAttDf),
     nodesVizAtt=nodesVizAtt,
     edgesVizAtt=edgesVizAtt,
-    nodes=nodes,
-    edges=cbind(edges,edgesLabel),
+    nodes=as.data.frame(nodes),
+    edges=as.data.frame(cbind(edges,edgesLabel)),
     graph=XML::saveXML(xmlFile, encoding=encoding)
     )
   
@@ -723,3 +741,12 @@ write.gexf <- function(
     print(results, file=output, replace=TRUE)
   }
 }
+
+
+#' @export
+#' @rdname gexf-class
+write.gexf <- function(...) {
+  warning("In future versions, rgexf 2.0, this function will be",
+          " the equivalent of -print(..., file=)-, and replaced by -gexf-")
+  gexf(...)
+}
diff --git a/README.Rmd b/README.Rmd
index e42ce72..6c38bf7 100644
--- a/README.Rmd
+++ b/README.Rmd
@@ -6,21 +6,28 @@ output: github_document
 [![Downloads](https://cranlogs.r-pkg.org/badges/grand-total/rgexf)](http://cran.rstudio.com/package=rgexf)
 [![Travis-CI Build Status](https://travis-ci.org/gvegayon/rgexf.svg?branch=master)](https://travis-ci.org/gvegayon/rgexf)
 [![AppVeyor Build Status](https://ci.appveyor.com/api/projects/status/github/gvegayon/rgexf?branch=master&svg=true)](https://ci.appveyor.com/project/gvegayon/rgexf)
+[![Coverage Status](https://img.shields.io/codecov/c/github/gvegayon/rgexf/master.svg)](https://codecov.io/github/gvegayon/rgexf?branch=master)
 
 # rgexf: Build, Import and Export GEXF Graph Files
 
 The first R package to work with GEXF graph files (used in Gephi and others). Using XML library, it allows the user to easily build/read graph files including attributes, GEXF viz attributes (such as colour, size, and position), network dynamics (for both edges and nodes, including spells) and edges weighting. Users can build/handle graphs element-by-element or massively through data-frames, visualize the graph on a web browser through sigmajs javascript library and interact with the igraph package.
 
 ## News ##
-[2016-11-08] Restarting the project.
-[2015-02-03] Version 0.15.2.3 of rgexf is on CRAN. Just updating emails...
-[2014-03-10] Version 0.14.9 of rgexf is on CRAN! solves issues 15-18. Thanks =).
-[2013-08-07] Version 0.13.8 of rgexf is on CRAN! New plot.gexf method and igraph integration working =).
-[2013-05-09] Version 0.13.05 of rgexf (transitory) solves issues N 9 & 10. Looking forward for the next CRAN version.
-[2013-03-14] Version 0.13.03 of rgexf is on its way to CRAN. It now supports working with spells!
-[2013-01-04] Version 0.13.01 of rgexf is on its way to CRAN. Significant improvements and new features!
-[2012-06-19] Version 0.12.06 of rgexf is on CRAN! Now it can be directly download from R.
-[2012-03-29] Version 0.12.03.29 of rgexf has been released including many bug fixes. Please download the lastest version to check it out.
+- [2016-11-08] Restarting the project.
+- [2015-02-03] Version 0.15.2.3 of rgexf is on CRAN. Just updating emails...
+- [2014-03-10] Version 0.14.9 of rgexf is on CRAN! solves issues 15-18. Thanks =).
+- [2013-08-07] Version 0.13.8 of rgexf is on CRAN! New plot.gexf method and igraph
+  integration working =).
+- [2013-05-09] Version 0.13.05 of rgexf (transitory) solves issues N 9 & 10. Looking
+  forward for the next CRAN version.
+- [2013-03-14] Version 0.13.03 of rgexf is on its way to CRAN. It now supports
+  working with spells!
+- [2013-01-04] Version 0.13.01 of rgexf is on its way to CRAN. Significant
+  improvements and new features!
+- [2012-06-19] Version 0.12.06 of rgexf is on CRAN! Now it can be directly download
+  from R.
+- [2012-03-29] Version 0.12.03.29 of rgexf has been released including many bug
+  fixes. Please download the lastest version to check it out.
 
 ## Example 1: Static net ##
 ```{r}
diff --git a/build_rgexf.sh b/build_rgexf.sh
deleted file mode 100644
index 6edb4f7..0000000
--- a/build_rgexf.sh
+++ /dev/null
@@ -1,8 +0,0 @@
-cd ..
-R CMD REMOVE rgexf
-rm -f rgexf_*
-R CMD build rgexf
-R CMD check --as-cran rgexf_*
-R CMD INSTALL rgexf_*
-cd rgexf
-# Rscript test.rgexf.R
diff --git a/codecov.yml b/codecov.yml
new file mode 100644
index 0000000..69cb760
--- /dev/null
+++ b/codecov.yml
@@ -0,0 +1 @@
+comment: false
diff --git a/demo/gexf.R b/demo/gexf.R
index b538152..84f60d6 100644
--- a/demo/gexf.R
+++ b/demo/gexf.R
@@ -42,32 +42,32 @@ edge.att
 ################################################################################
 # First example: a simple net
 pause()
-write.gexf(nodes=people, edges=relations)
+gexf(nodes=people, edges=relations)
 
 ################################################################################
 # Second example: a simple net with nodes attributes
 pause()
-write.gexf(nodes=people, edges=relations, nodesAtt=node.att)
+gexf(nodes=people, edges=relations, nodesAtt=node.att)
 
 ################################################################################
 # Third example: a simple net with dynamic nodes
 pause()
-write.gexf(nodes=people, edges=relations, nodeDynamic=time.nodes)
+gexf(nodes=people, edges=relations, nodeDynamic=time.nodes)
 
 ################################################################################
 # Fourth example: a simple net with dynamic nodes with attributes
 pause()
-write.gexf(nodes=people, edges=relations, nodeDynamic=time.nodes, nodesAtt=node.att)
+gexf(nodes=people, edges=relations, nodeDynamic=time.nodes, nodesAtt=node.att)
 
 ################################################################################
 # Fifth example: a simple net with dynamic edges with attributes
 pause()
-write.gexf(nodes=people, edges=relations, edgeDynamic=time.edges, edgesAtt=edge.att)
+gexf(nodes=people, edges=relations, edgeDynamic=time.edges, edgesAtt=edge.att)
 
 ################################################################################
 # Sixth example: a simple net with dynamic edges and nodes with attributes
 pause()
-write.gexf(nodes=people, edges=relations, edgeDynamic=time.edges, edgesAtt=edge.att,
+gexf(nodes=people, edges=relations, edgeDynamic=time.edges, edgesAtt=edge.att,
      nodeDynamic=time.nodes, nodesAtt=node.att)
 
 ################################################################################
@@ -90,7 +90,7 @@ colnames(edgecolors) <- c("r", "b", "g", "a")
 nodetruefalse <- data.frame(nodetrue=rnorm(NROW(people)) > 0)
 edgetruefalse <- data.frame(edgetrue=rnorm(NROW(relations)) > 0)
 
-grafo <- write.gexf(nodes=people, edges=relations, 
+grafo <- gexf(nodes=people, edges=relations, 
               nodesAtt=cbind(imagee,nodetruefalse),
               nodesVizAtt=list(
                 shape=c("rectangle", "square", "triangle", "diamond"),
@@ -105,4 +105,4 @@ grafo <- write.gexf(nodes=people, edges=relations,
                 ), 
               edgesAtt=edgetruefalse)
 
-print(grafo)
\ No newline at end of file
+print(grafo)
diff --git a/demo/gexfattributes.R b/demo/gexfattributes.R
index 112f46f..0f80a74 100644
--- a/demo/gexfattributes.R
+++ b/demo/gexfattributes.R
@@ -38,6 +38,6 @@ edge.att
 # before the last closing 
 # parenthesis in the following function
 
-write.gexf(nodes=people, edges=relations, nodesAtt=node.att, edgesAtt=edge.att)
+gexf(nodes=people, edges=relations, nodesAtt=node.att, edgesAtt=edge.att)
 
-################################################################################
\ No newline at end of file
+################################################################################
diff --git a/demo/gexfbasic.R b/demo/gexfbasic.R
index e768d06..d713956 100644
--- a/demo/gexfbasic.R
+++ b/demo/gexfbasic.R
@@ -33,6 +33,6 @@ pause()
 # before the last closing 
 # parenthesis in the following function
 
-write.gexf(nodes=people, edges=relations)
+gexf(nodes=people, edges=relations)
 
-################################################################################  
\ No newline at end of file
+################################################################################  
diff --git a/demo/gexfdynamic.R b/demo/gexfdynamic.R
index 27f381e..c34021f 100644
--- a/demo/gexfdynamic.R
+++ b/demo/gexfdynamic.R
@@ -42,4 +42,4 @@ time.edges
 # parenthesis in the following function
 
 pause()
-write.gexf(nodes=people, edges=relations, nodeDynamic=time.nodes)
\ No newline at end of file
+gexf(nodes=people, edges=relations, nodeDynamic=time.nodes)
diff --git a/demo/gexfdynamicandatt.R b/demo/gexfdynamicandatt.R
index dc55c49..63a9e71 100644
--- a/demo/gexfdynamicandatt.R
+++ b/demo/gexfdynamicandatt.R
@@ -52,5 +52,5 @@ time.edges
 # parenthesis in the following function
 
 pause()
-write.gexf(nodes=people, edges=relations, edgeDynamic=time.edges, edgesAtt=edge.att,
-     nodeDynamic=time.nodes, nodesAtt=node.att)
\ No newline at end of file
+gexf(nodes=people, edges=relations, edgeDynamic=time.edges, edgesAtt=edge.att,
+     nodeDynamic=time.nodes, nodesAtt=node.att)
diff --git a/demo/gexffull.R b/demo/gexffull.R
index 2bc4605..da311f3 100644
--- a/demo/gexffull.R
+++ b/demo/gexffull.R
@@ -77,7 +77,7 @@ thick<-1:9
 
 pause()
 
-write.gexf(nodes=people, edgesWeight=thick, edges=relations,
+gexf(nodes=people, edgesWeight=thick, edges=relations,
            edgeDynamic=time.edges, edgesAtt=edge.att, nodeDynamic=time.nodes,
            nodesAtt=node.att,
            nodesVizAtt = list(
diff --git a/demo/gexfplot.R b/demo/gexfplot.R
index 2d06525..b2d9be0 100644
--- a/demo/gexfplot.R
+++ b/demo/gexfplot.R
@@ -7,7 +7,7 @@ relations <- data.frame(source = c(1,1,1,2,3,4), target = c(4,2,3,3,4,2))
 node.att <- data.frame(letrafavorita=letters[1:4], numbers=1:4)
 
 # No position arguments, so it will be random.
-simple.gexf <- write.gexf(nodes=people, edges=relations, nodesAtt=node.att)
+simple.gexf <- gexf(nodes=people, edges=relations, nodesAtt=node.att)
 gexf(simple.gexf)
 
 #### 'Les Miserable's example of Sigmajs ####
@@ -75,7 +75,7 @@ positions <- cbind(positions, 0) # needs a z axis
 
 
 
-graph <- write.gexf(nodes=nodes,
+graph <- gexf(nodes=nodes,
                     edges=relations,
                     nodesVizAtt=list(
                       color=nodecolors,
diff --git a/demo/gexfrandom.R b/demo/gexfrandom.R
index 6fe4919..5b00559 100644
--- a/demo/gexfrandom.R
+++ b/demo/gexfrandom.R
@@ -68,7 +68,7 @@ pos3[,1] <- pos3[,1] + max(pos2[,1])-min(pos[,1])
 pause()
 
 # Plotting
-graph <- write.gexf(
+graph <- gexf(
   rbind(vertex1,vertex2,vertex3), 
   rbind(edges1, edges2,edges3), 
   nodesVizAtt=list(
diff --git a/demo/gexftwitter.R b/demo/gexftwitter.R
index fb898a5..510121a 100644
--- a/demo/gexftwitter.R
+++ b/demo/gexftwitter.R
@@ -31,6 +31,6 @@ relations<- subset(followers, select=c(source, target))
 # Creating the follower-following network in gexf format with some nodes' attribute
 pause()
 
-x1 <- write.gexf(nodos, relations, keepFactors=F, nodesAtt=nodos.att)
+x1 <- gexf(nodos, relations, keepFactors=F, nodesAtt=nodos.att)
 
 summary(x1)
diff --git a/man/write.gexf.Rd b/man/gexf-class.Rd
similarity index 88%
rename from man/write.gexf.Rd
rename to man/gexf-class.Rd
index 44a85e0..a1206e1 100644
--- a/man/write.gexf.Rd
+++ b/man/gexf-class.Rd
@@ -1,19 +1,22 @@
 % Generated by roxygen2: do not edit by hand
 % Please edit documentation in R/rgexf.r
-\name{write.gexf}
+\name{gexf-class}
+\alias{gexf}
+\alias{gexf-class}
 \alias{write.gexf}
-\title{Builds a graph of \code{gexf} class}
+\title{Creates an object of class \code{gexf}}
 \usage{
-write.gexf(nodes, edges, edgesLabel = NULL, edgesId = NULL,
-  edgesAtt = NULL, edgesWeight = NULL, edgesVizAtt = list(color = NULL,
-  size = NULL, shape = NULL), nodesAtt = NULL, nodesVizAtt = list(color =
-  NULL, position = NULL, size = NULL, shape = NULL, image = NULL),
-  nodeDynamic = NULL, edgeDynamic = NULL, digits = getOption("digits"),
-  output = NA, tFormat = "double", defaultedgetype = "undirected",
-  meta = list(creator = "NodosChile", description =
-  "A graph file writing in R using \\"rgexf\\"", keywords =
-  "gexf graph, NodosChile, R, rgexf"), keepFactors = FALSE,
+gexf(nodes, edges, edgesLabel = NULL, edgesId = NULL, edgesAtt = NULL,
+  edgesWeight = NULL, edgesVizAtt = list(color = NULL, size = NULL, shape =
+  NULL), nodesAtt = NULL, nodesVizAtt = list(color = NULL, position = NULL,
+  size = NULL, shape = NULL, image = NULL), nodeDynamic = NULL,
+  edgeDynamic = NULL, digits = getOption("digits"), output = NA,
+  tFormat = "double", defaultedgetype = "undirected", meta = list(creator
+  = "NodosChile", description = "A graph file writing in R using \\"rgexf\\"",
+  keywords = "gexf graph, NodosChile, R, rgexf"), keepFactors = FALSE,
   encoding = "UTF-8", vers = "1.3")
+
+write.gexf(...)
 }
 \arguments{
 \item{nodes}{A two-column data-frame or matrix of \dQuote{id}s and
@@ -71,6 +74,8 @@ the graph as a GEXF file.}
 
 \item{vers}{Character scalar. Version of the GEXF format to generate.
 By default \code{"1.3"}.}
+
+\item{...}{Passed to \code{gexf}.}
 }
 \value{
 A \code{gexf} class object (list). Contains the following: \itemize{
@@ -86,7 +91,7 @@ edges' ids, labels, sources, targets and weights.  \item \code{graph} :
 (String) GEXF (XML) representation of the graph.  }
 }
 \description{
-\code{write.gexf} takes a \code{node} matrix (or dataframe) and an
+Takes a \code{node} matrix (or dataframe) and an
 \code{edge} matrix (or dataframe) and creates a \code{gexf} object
 containing a data-frame representation and a gexf representation of a graph.
 }
diff --git a/man/gexf-methods.Rd b/man/gexf-methods.Rd
index fe3fb04..7a4884c 100644
--- a/man/gexf-methods.Rd
+++ b/man/gexf-methods.Rd
@@ -67,7 +67,7 @@ requires this).  to
                         target=c(4,2,3,3,4,2,4,1,1))
     
     # Building gexf graph
-    mygraph <- write.gexf(nodes=people, edges=relations)
+    mygraph <- gexf(nodes=people, edges=relations)
     
     # Summary and pring
     summary(mygraph)
diff --git a/man/rgexf-package.Rd b/man/rgexf-package.Rd
index 5b3c639..fc7a004 100644
--- a/man/rgexf-package.Rd
+++ b/man/rgexf-package.Rd
@@ -3,7 +3,6 @@
 \docType{package}
 \name{rgexf-package}
 \alias{gephi}
-\alias{gexf}
 \alias{rgexf}
 \alias{rgexf-package}
 \title{Build, Import and Export GEXF Graph Files}
@@ -26,9 +25,6 @@ attributes and colors.
 
 Please visit the project home for more information:
 \url{https://github.com/gvegayon/rgexf}.
-
-\tabular{ll}{ Package: \tab rgexf\cr Type: \tab Package\cr Version: \tab
-0.16.9000\cr Date: \tab 2016-11-08\cr License: \tab MIT+file\cr }
 }
 \note{
 See the GEXF primer for details on the GEXF graph format:
diff --git a/only_comp.sh b/only_comp.sh
deleted file mode 100644
index 6fdb233..0000000
--- a/only_comp.sh
+++ /dev/null
@@ -1,8 +0,0 @@
-cd ..
-R CMD REMOVE rgexf
-rm -f rgexf_*
-R CMD build rgexf
-#R CMD check --as-cran rgexf_*
-R CMD INSTALL rgexf_*
-cd rgexf
-# Rscript test.rgexf.R
diff --git a/rgexf.Rproj b/rgexf.Rproj
index 4d263d7..ff46899 100644
--- a/rgexf.Rproj
+++ b/rgexf.Rproj
@@ -17,4 +17,4 @@ AutoAppendNewline: Yes
 BuildType: Package
 PackageUseDevtools: Yes
 PackageInstallArgs: --no-multiarch --with-keep.source
-PackageRoxygenize: rd,collate,namespace,vignette
+PackageRoxygenize: rd,collate,namespace
diff --git a/tests/testthat.R b/tests/testthat.R
new file mode 100644
index 0000000..46b8fd6
--- /dev/null
+++ b/tests/testthat.R
@@ -0,0 +1,4 @@
+library(testthat)
+library(rgexf)
+
+test_check("rgexf")
diff --git a/tests/testthat/test-test-gexf.R b/tests/testthat/test-test-gexf.R
new file mode 100644
index 0000000..f921d4f
--- /dev/null
+++ b/tests/testthat/test-test-gexf.R
@@ -0,0 +1,33 @@
+context("gexf function")
+
+nodes <- cbind(a=1:10, b=letters[1:10])
+edges <- matrix(sample(1:10, 20, TRUE), ncol=2)
+
+# ------------------------------------------------------------------------------
+test_that("data.frame or matrix work OK", {
+  
+  ans0 <- gexf(as.data.frame(nodes), as.data.frame(edges))
+  ans1 <- gexf(nodes, edges)
+  
+  expect_equal(ans0,ans1)
+})
+
+# ------------------------------------------------------------------------------
+test_that("errors", {
+  # edge.list
+  expect_error(edge.list(cbind(1:10)), "number of columns")
+  expect_error(edge.list(list), "class not supported")
+  
+  # gexf
+  expect_error(gexf(nodes[,-1,drop=FALSE], edges), "nodes.+columns")
+  expect_error(gexf(nodes, edges[,-1,drop=FALSE]), "edges.+columns")
+  expect_error(gexf(nodes, edges, digits = 1.1), "digits")
+  expect_error(gexf(nodes, edges, nodeDynamic = nodes[-1,,drop=TRUE]),
+               "number of rows")
+  expect_error(gexf(nodes, edges, edgeDynamic = edges[-1,,drop=TRUE]),
+               "number of rows")
+  
+  expect_error(gexf(nodes, edges, nodeDynamic = list(1)),"should be a ")
+  expect_error(gexf(nodes, edges, edgeDynamic = list(1)),"should be a ")
+  
+})
diff --git a/vignettes/rgexf.Rmd b/vignettes/rgexf.Rmd
index dcaa63e..01ffe62 100644
--- a/vignettes/rgexf.Rmd
+++ b/vignettes/rgexf.Rmd
@@ -64,7 +64,7 @@ pos3 <- pos
 pos3[,1] <- pos3[,1] + max(pos2[,1])-min(pos[,1])
 
 # Plotting
-graph <- write.gexf(
+graph <- gexf(
   rbind(vertex1,vertex2,vertex3), 
   rbind(edges1, edges2,edges3), 
   nodesVizAtt=list(