Support single series value

Author: NathanBaulch

AsciiChart.Sharp.Tests/Tests.cs

@@ -20,6 +20,7 @@ public void TestPlot(double[] series, Options opts, string expected)
 
         private static object[][] Cases =
         {
+            new object[] { new double[] { 1 }, null, " 1.00 ┼ " },
             new object[] { new double[] { 1, 1, 1, 1, 1 }, null, " 1.00 ┼──── " },
             new object[] { new double[] { 0, 0, 0, 0, 0 }, null, " 0.00 ┼──── " },
             new object[]

AsciiChart.Sharp/AsciiChart.cs

@@ -36,16 +36,13 @@ public static string Plot(IEnumerable<double> series, Options options = null)
             var yAxisLabels = GetYAxisLabels(max, range, rows, options);
             ApplyYAxisLabels(resultArray, yAxisLabels, columnIndexOfFirstDataPoint);
 
+            var rowIndex0 = Math.Round(seriesList[0] * ratio, MidpointRounding.AwayFromZero) - min2;
+            resultArray[(int) (rows - rowIndex0)][columnIndexOfFirstDataPoint - 1] = "┼";
+
             for (var x = 0; x < seriesList.Count - 1; x++)
             {
-                var rowIndex0 = Math.Round(seriesList[x] * ratio, MidpointRounding.AwayFromZero) - min2;
                 var rowIndex1 = Math.Round(seriesList[x + 1] * ratio, MidpointRounding.AwayFromZero) - min2;
 
-                if (x == 0)
-                {
-                    resultArray[(int) (rows - rowIndex0)][columnIndexOfFirstDataPoint - 1] = "┼";
-                }
-
                 if (rowIndex0 == rowIndex1)
                 {
                     resultArray[(int) (rows - rowIndex0)][x + columnIndexOfFirstDataPoint] = "─";
@@ -60,6 +57,8 @@ public static string Plot(IEnumerable<double> series, Options options = null)
                     {
                         resultArray[(int) (rows - y)][x + columnIndexOfFirstDataPoint] = "│";
                     }
+
+                    rowIndex0 = rowIndex1;
                 }
             }