Add tests for Hstore

README.md

@@ -174,6 +174,10 @@ To setup the normal test environment run the following SQL:
     create user pgx_md5 password 'secret';
     create database pgx_test;
 
+Connect to database pgx_test and run:
+
+    create extension hstore;
+
 Next open connection_settings_test.go.example and make a copy without the
 .example. If your PostgreSQL server is accepting connections on 127.0.0.1,
 then you are done.

hstore.go

@@ -81,6 +81,9 @@ func parseHstoreToNullHstore(s string) (store map[string]NullString, err error)
 }
 
 func ParseHstore(s string) (k []string, v []NullString, err error) {
+	if s == "" {
+		return
+	}
 
 	buf := bytes.Buffer{}
 	keys := []string{}

hstore_test.go

@@ -0,0 +1,71 @@
+package pgx_test
+
+import (
+	"github.com/jackc/pgx"
+	"testing"
+)
+
+func TestHstoreTranscode(t *testing.T) {
+	t.Parallel()
+
+	conn := mustConnect(t, *defaultConnConfig)
+	defer closeConn(t, conn)
+
+	type test struct {
+		hstore      pgx.Hstore
+		description string
+	}
+
+	tests := []test{
+		{pgx.Hstore{}, "empty"},
+		{pgx.Hstore{"foo": "bar"}, "single key/value"},
+		{pgx.Hstore{"foo": "bar", "baz": "quz"}, "multiple key/values"},
+		{pgx.Hstore{"NULL": "bar"}, `string "NULL" key`},
+		{pgx.Hstore{"foo": "NULL"}, `string "NULL" value`},
+	}
+
+	specialStringTests := []struct {
+		input       string
+		description string
+	}{
+		{`"`, `double quote (")`},
+		{`'`, `single quote (')`},
+		{`\`, `backslash (\)`},
+		{`\\`, `multiple backslashes (\\)`},
+		{`=>`, `separator (=>)`},
+		{` `, `space`},
+		{`\ / / \\ => " ' " '`, `multiple special characters`},
+	}
+	for _, sst := range specialStringTests {
+		tests = append(tests, test{pgx.Hstore{sst.input + "foo": "bar"}, "key with " + sst.description + " at beginning"})
+		tests = append(tests, test{pgx.Hstore{"foo" + sst.input + "foo": "bar"}, "key with " + sst.description + " in middle"})
+		tests = append(tests, test{pgx.Hstore{"foo" + sst.input: "bar"}, "key with " + sst.description + " at end"})
+		tests = append(tests, test{pgx.Hstore{sst.input: "bar"}, "key is " + sst.description})
+
+		tests = append(tests, test{pgx.Hstore{"foo": sst.input + "bar"}, "value with " + sst.description + " at beginning"})
+		tests = append(tests, test{pgx.Hstore{"foo": "bar" + sst.input + "bar"}, "value with " + sst.description + " in middle"})
+		tests = append(tests, test{pgx.Hstore{"foo": "bar" + sst.input}, "value with " + sst.description + " at end"})
+		tests = append(tests, test{pgx.Hstore{"foo": sst.input}, "value is " + sst.description})
+	}
+
+	for _, tt := range tests {
+		var result pgx.Hstore
+		err := conn.QueryRow("select $1::hstore", tt.hstore).Scan(&result)
+		if err != nil {
+			t.Errorf(`%s: QueryRow.Scan returned an error: %v`, tt.description, err)
+		}
+
+		for key, inValue := range tt.hstore {
+			outValue, ok := result[key]
+			if ok {
+				if inValue != outValue {
+					t.Errorf(`%s: Key %s mismatch - expected %s, received %s`, tt.description, key, inValue, outValue)
+				}
+			} else {
+				t.Errorf(`%s: Missing key %s`, tt.description, key)
+			}
+		}
+
+		ensureConnValid(t, conn)
+	}
+}