diff --git a/cmd/stattocsv/main.go b/cmd/stattocsv/main.go
index 321f48d..64743f2 100644
--- a/cmd/stattocsv/main.go
+++ b/cmd/stattocsv/main.go
@@ -6,6 +6,7 @@ package main
 // (e.g. it may be the number of days since January 1, 1960).
 
 import (
+	"encoding/csv"
 	"fmt"
 	"os"
 	"strings"
@@ -61,5 +62,8 @@ func main() {
 		rdr = stata
 	}
 
-	datareader.DoConversion(rdr)
+	err = datareader.ToCsv(rdr, 1000, csv.NewWriter(os.Stdout))
+	if err != nil {
+		panic(err)
+	}
 }
diff --git a/convert.go b/convert.go
index 30f0032..ab293cd 100644
--- a/convert.go
+++ b/convert.go
@@ -2,28 +2,25 @@ package datareader
 
 import (
 	"encoding/csv"
+	"errors"
 	"fmt"
 	"io"
-	"os"
 	"time"
 )
 
-func DoConversion(rdr StatfileReader) {
-
-	w := csv.NewWriter(os.Stdout)
-
+func ToCsv(rdr StatfileReader, rows int, w *csv.Writer) error {
 	ncol := len(rdr.ColumnNames())
 	if err := w.Write(rdr.ColumnNames()); err != nil {
-		panic(err)
+		return err
 	}
 
 	row := make([]string, ncol)
 
 	for {
-		chunk, err := rdr.Read(1000)
-		if err != nil && err != io.EOF {
-			panic(err)
-		} else if chunk == nil || err == io.EOF {
+		chunk, err := rdr.Read(rows)
+		if err != nil && !errors.Is(err, io.EOF) {
+			return err
+		} else if chunk == nil || errors.Is(err, io.EOF) {
 			break
 		}
 
@@ -39,7 +36,7 @@ func DoConversion(rdr StatfileReader) {
 
 		missing := make([][]bool, ncol)
 
-		for j := 0; j < ncol; j++ {
+		for j := range ncol {
 			missing[j] = chunk[j].Missing()
 			dcol := chunk[j].Data()
 			switch v := dcol.(type) {
@@ -50,37 +47,39 @@ func DoConversion(rdr StatfileReader) {
 			case []string:
 				stringcols[j] = v
 			default:
-				panic(fmt.Sprintf("unknown type: %T", dcol))
+				return fmt.Errorf("unknown type: %T", dcol)
 			}
 		}
 
 		for i := range nrow {
 			for j := range ncol {
-				if numbercols[j] != nil {
+				switch {
+				case numbercols[j] != nil:
 					if missing[j] == nil || !missing[j][i] {
 						row[j] = fmt.Sprintf("%f", numbercols[j][i])
 					} else {
 						row[j] = ""
 					}
-				} else if stringcols[j] != nil {
+				case stringcols[j] != nil:
 					if missing[j] == nil || !missing[j][i] {
 						row[j] = stringcols[j][i]
 					} else {
 						row[j] = ""
 					}
-				} else if timecols[j] != nil {
+				case timecols[j] != nil:
 					if missing[j] == nil || !missing[j][i] {
-						row[j] = fmt.Sprintf("%v", timecols[j][i])
+						row[j] = timecols[j][i].String()
 					} else {
 						row[j] = ""
 					}
 				}
 			}
-			if err := w.Write(row); err != nil {
-				panic(err)
+			if werr := w.Write(row); werr != nil {
+				return werr
 			}
 		}
 	}
 
 	w.Flush()
+	return nil
 }
diff --git a/convert_test.go b/convert_test.go
new file mode 100644
index 0000000..f2dd8e3
--- /dev/null
+++ b/convert_test.go
@@ -0,0 +1,74 @@
+package datareader_test
+
+import (
+	"bytes"
+	"encoding/csv"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/dominodatalab/datareader"
+	"github.com/stretchr/testify/require"
+)
+
+type testFile struct {
+	path string
+}
+
+func TestToCsvConvertsSAS(t *testing.T) {
+	files, err := filepath.Glob("test_files/data/*.sas7bdat")
+	require.NoError(t, err)
+
+	testcases := map[string]testFile{}
+	for _, f := range files {
+		testcases["converts "+f] = testFile{path: f}
+	}
+
+	for name, tt := range testcases {
+		t.Run(name, func(t *testing.T) {
+			f, err := os.Open(tt.path)
+			require.NoError(t, err)
+			defer f.Close()
+
+			sas, err := datareader.NewSAS7BDATReader(f)
+			require.NoError(t, err)
+			sas.ConvertDates = true
+			sas.TrimStrings = true
+
+			buf := new(bytes.Buffer)
+			w := csv.NewWriter(buf)
+			err = datareader.ToCsv(sas, 100, w)
+
+			require.NoError(t, err)
+		})
+	}
+}
+
+func TestToCsvConvertsStata(t *testing.T) {
+	files, err := filepath.Glob("test_files/data/*.dta")
+	require.NoError(t, err)
+
+	testcases := map[string]testFile{}
+	for _, f := range files {
+		testcases["converts "+f] = testFile{path: f}
+	}
+
+	for name, tt := range testcases {
+		t.Run(name, func(t *testing.T) {
+			f, err := os.Open(tt.path)
+			require.NoError(t, err)
+			defer f.Close()
+
+			stata, err := datareader.NewStataReader(f)
+			require.NoError(t, err)
+			stata.ConvertDates = true
+			stata.InsertCategoryLabels = true
+			stata.InsertStrls = true
+
+			buf := new(bytes.Buffer)
+			w := csv.NewWriter(buf)
+			err = datareader.ToCsv(stata, 100, w)
+			require.NoError(t, err)
+		})
+	}
+}
diff --git a/go.mod b/go.mod
index 8220880..7ebab90 100644
--- a/go.mod
+++ b/go.mod
@@ -4,21 +4,25 @@ go 1.22.3
 
 require (
 	github.com/pkg/errors v0.9.1
+	github.com/stretchr/testify v1.9.0
 	golang.org/x/text v0.15.0
 	gotest.tools/gotestsum v1.11.0
 )
 
 require (
 	github.com/bitfield/gotestdox v0.2.1 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/dnephin/pflag v1.0.7 // indirect
 	github.com/fatih/color v1.15.0 // indirect
 	github.com/fsnotify/fsnotify v1.5.4 // indirect
 	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.19 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	golang.org/x/mod v0.12.0 // indirect
 	golang.org/x/sync v0.3.0 // indirect
 	golang.org/x/sys v0.10.0 // indirect
 	golang.org/x/term v0.10.0 // indirect
 	golang.org/x/tools v0.11.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
diff --git a/go.sum b/go.sum
index 3bfe423..adddb00 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,7 @@
 github.com/bitfield/gotestdox v0.2.1 h1:Zj8IMLAO5/oiAKoMmtN96eyFiPZraJRTH2p0zDgtxc0=
 github.com/bitfield/gotestdox v0.2.1/go.mod h1:D+gwtS0urjBrzguAkTM2wodsTQYFHdpx8eqRJ3N+9pY=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/dnephin/pflag v1.0.7 h1:oxONGlWxhmUct0YzKTgrpQv9AUA1wtPBn7zuSjJqptk=
 github.com/dnephin/pflag v1.0.7/go.mod h1:uxE91IoWURlOiTUIA8Mq5ZZkAv3dPUfZNaT80Zm7OQE=
 github.com/fatih/color v1.15.0 h1:kOqh6YHBtK8aywxGerMG2Eq3H6Qgoqeo13Bk2Mv/nBs=
@@ -19,9 +21,13 @@ github.com/mattn/go-isatty v0.0.19 h1:JITubQf0MOLdlGRuRq+jtsDlekdYPia9ZFsB8h/APP
 github.com/mattn/go-isatty v0.0.19/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/rogpeppe/go-internal v1.11.0 h1:cWPaGQEPrBb5/AsnsZesgZZ9yb1OQ+GOISoDNXVBh4M=
 github.com/rogpeppe/go-internal v1.11.0/go.mod h1:ddIwULY96R17DhadqLgMfk9H9tvdUzkipdSkR5nkCZA=
 github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
+github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
+github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
@@ -89,6 +95,10 @@ golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8T
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gotest.tools/gotestsum v1.11.0 h1:A88/QWw7acMjZH1dMe6KZFhw32odUOIjCiAU/Q4n3mI=
 gotest.tools/gotestsum v1.11.0/go.mod h1:cUOKgFEvWAP0twchmiOvdzX0SBZX0UI58bGRpRIu4xs=
 gotest.tools/v3 v3.3.0 h1:MfDY1b1/0xN1CyMlQDac0ziEy9zJQd9CXBRRDHw2jJo=