Fix bug where TextWrapper didn't cope gracefully with negative columnWidth. Also fix up old broken tests

Author: NeilMacMullen

src/CommandLine/Text/TextWrapper.cs

@@ -41,7 +41,8 @@ public TextWrapper(string input)
         /// <returns>this</returns>
         public TextWrapper WordWrap(int columnWidth)
         {
-
+            //ensure we always use at least 1 column even if the client has told us there's no space available
+            columnWidth = Math.Max(1, columnWidth);
             lines= lines
                 .SelectMany(line => WordWrapLine(line, columnWidth))
                 .ToArray();

tests/CommandLine.Tests/Unit/Core/TextWrapperTests.cs

@@ -1,4 +1,5 @@
-using CommandLine.Tests.Fakes;
+using System;
+using System.Linq;
 using CommandLine.Text;
 using FluentAssertions;
 using Xunit;
@@ -11,110 +12,120 @@ private string NormalizeLineBreaks(string str)
         {
             return str.Replace("\r", "");
         }
-        private void EnsureEquivalent(string a,string b)
+
+        private void EnsureEquivalent(string a, string b)
         {
             //workaround build system line-end inconsistencies
             NormalizeLineBreaks(a).Should().Be(NormalizeLineBreaks(b));
         }
 
-        
+
         [Fact]
-        public void IndentWorksCorrectly()
+        public void ExtraSpacesAreTreatedAsNonBreaking()
         {
+            var input =
+                "here is some text                                                          with some extra spacing";
+            var expected = @"here is some text
+with some extra
+spacing";
+            var wrapper = new TextWrapper(input);
+            EnsureEquivalent(wrapper.WordWrap(20).ToText(), expected);
+        }
 
+
+        [Fact]
+        public void IndentWorksCorrectly()
+        {
             var input =
                 @"line1
 line2";
             var expected = @"  line1
   line2";
             var wrapper = new TextWrapper(input);
-            EnsureEquivalent(wrapper.Indent(2).ToText(),expected);
-
+            EnsureEquivalent(wrapper.Indent(2).ToText(), expected);
         }
 
         [Fact]
-        public void SimpleWrappingIsAsExpected()
+        public void LongWordsAreBroken()
         {
-
             var input =
-                @"here is some text that needs wrapping";
-            var expected = @"here is
-some text
-that needs
-wrapping";
+                "here is some text that contains a veryLongWordThatWontFitOnASingleLine";
+            var expected = @"here is some text
+that contains a
+veryLongWordThatWont
+FitOnASingleLine";
             var wrapper = new TextWrapper(input);
-            EnsureEquivalent(wrapper.WordWrap(10).ToText(),expected);
-
+            EnsureEquivalent(wrapper.WordWrap(20).ToText(), expected);
         }
 
         [Fact]
-        public void WrappingAvoidsBreakingWords()
+        public void NegativeColumnWidthStillProducesOutput()
         {
-
-            var input =
-                @"here hippopotamus is some text that needs wrapping";
-            var expected = @"here
-hippopotamus is
-some text that
-needs wrapping";
+            var input = @"test";
+            var expected = string.Join(Environment.NewLine, input.Select(c => c.ToString()));
             var wrapper = new TextWrapper(input);
-            EnsureEquivalent(wrapper.WordWrap(15).ToText(),expected);
-
+            EnsureEquivalent(wrapper.WordWrap(-1).ToText(), expected);
         }
 
         [Fact]
-        public void WrappingObeysLineBreaksOfAllStyles()
+        public void SimpleWrappingIsAsExpected()
         {
-
             var input =
-                "here is some text\nthat needs\r\nwrapping";
-            var expected = @"here is some text
+                @"here is some text that needs wrapping";
+            var expected = @"here is
+some text
 that needs
 wrapping";
             var wrapper = new TextWrapper(input);
-            EnsureEquivalent(wrapper.WordWrap(20).ToText(),expected);
-
+            EnsureEquivalent(wrapper.WordWrap(10).ToText(), expected);
         }
 
-
         [Fact]
-        public void WrappingPreservesSubIndentation()
+        public void SingleColumnStillProducesOutputForSubIndentation()
         {
-
-            var input =
-                "here is some text\n   that needs wrapping where we want the wrapped part to preserve indentation\nand this part to not be indented";
-            var expected = @"here is some text
-   that needs
-   wrapping where we
-   want the wrapped
-   part to preserve
-   indentation
-and this part to not
-be indented";
+            var input = @"test
+    ind";
+
+            var expected = @"t
+e
+s
+t
+i
+n
+d";
             var wrapper = new TextWrapper(input);
-            EnsureEquivalent(wrapper.WordWrap(20).ToText(),expected);
-
+            EnsureEquivalent(wrapper.WordWrap(-1).ToText(), expected);
         }
 
         [Fact]
-        public void LongWordsAreBroken()
+        public void SpacesWithinStringAreRespected()
         {
-
             var input =
-                "here is some text that contains a veryLongWordThatWontFitOnASingleLine";
-            var expected = @"here is some text
-that contains a
-veryLongWordThatWont
-FitOnASingleLine";
+                "here     is some text with some extra spacing";
+            var expected = @"here     is some
+text with some extra
+spacing";
             var wrapper = new TextWrapper(input);
-            EnsureEquivalent(wrapper.WordWrap(20).ToText(),expected);
+            EnsureEquivalent(wrapper.WordWrap(20).ToText(), expected);
+        }
 
+        [Fact]
+        public void SubIndentationCorrectlyWrapsWhenColumnWidthRequiresIt()
+        {
+            var input = @"test
+    indented";
+            var expected = @"test
+    in
+    de
+    nt
+    ed";
+            var wrapper = new TextWrapper(input);
+            EnsureEquivalent(wrapper.WordWrap(6).ToText(), expected);
         }
 
         [Fact]
         public void SubIndentationIsPreservedWhenBreakingWords()
         {
-
             var input =
                 "here is some text that contains \n  a veryLongWordThatWontFitOnASingleLine";
             var expected = @"here is some text
@@ -123,59 +134,64 @@ that contains
   veryLongWordThatWo
   ntFitOnASingleLine";
             var wrapper = new TextWrapper(input);
-            EnsureEquivalent(wrapper.WordWrap(20).ToText(),expected);
-
+            EnsureEquivalent(wrapper.WordWrap(20).ToText(), expected);
         }
 
         [Fact]
-        public void SpacesWithinStringAreRespected()
+        public void WrappingAvoidsBreakingWords()
         {
-
             var input =
-                "here     is some text with some extra spacing";
-            var expected = @"here     is some
-text with some extra
-spacing";
+                @"here hippopotamus is some text that needs wrapping";
+            var expected = @"here
+hippopotamus is
+some text that
+needs wrapping";
             var wrapper = new TextWrapper(input);
-            EnsureEquivalent(wrapper.WordWrap(20).ToText(),expected);
-
+            EnsureEquivalent(wrapper.WordWrap(15).ToText(), expected);
         }
 
-        
-        [Fact]
-        public void ExtraSpacesAreTreatedAsNonBreaking()
-        {
 
-            var input =
-                "here is some text                                                          with some extra spacing";
-            var expected = @"here is some text
-with some extra
-spacing";
-            var wrapper = new TextWrapper(input);
-            EnsureEquivalent(wrapper.WordWrap(20).ToText(),expected);
-
-        }
-
-         
         [Fact]
         public void WrappingExtraSpacesObeySubIndent()
         {
-
             var input =
                 "here is some\n   text                                                          with some extra spacing";
             var expected = @"here is some
    text
    with some extra
    spacing";
             var wrapper = new TextWrapper(input);
-            EnsureEquivalent(wrapper.WordWrap(20).ToText(),expected);
-
+            EnsureEquivalent(wrapper.WordWrap(20).ToText(), expected);
         }
 
+        [Fact]
+        public void WrappingObeysLineBreaksOfAllStyles()
+        {
+            var input =
+                "here is some text\nthat needs\r\nwrapping";
+            var expected = @"here is some text
+that needs
+wrapping";
+            var wrapper = new TextWrapper(input);
+            EnsureEquivalent(wrapper.WordWrap(20).ToText(), expected);
+        }
 
 
+        [Fact]
+        public void WrappingPreservesSubIndentation()
+        {
+            var input =
+                "here is some text\n   that needs wrapping where we want the wrapped part to preserve indentation\nand this part to not be indented";
+            var expected = @"here is some text
+   that needs
+   wrapping where we
+   want the wrapped
+   part to preserve
+   indentation
+and this part to not
+be indented";
+            var wrapper = new TextWrapper(input);
+            EnsureEquivalent(wrapper.WordWrap(20).ToText(), expected);
+        }
     }
-
-
-    
 }