--diff option (experimental)

using an LCS algorithm (like diff)

bin/cmdtest.rb

@@ -560,6 +560,7 @@ module Cmdtest
       pr.add("",   "--version",      "show version")
       pr.add("-q", "--quiet",        "be more quiet")
       pr.add("-v", "--verbose",      "be more verbose")
+      pr.add("",   "--diff",         "experimental diff output")
       pr.add("",   "--fast",         "run fast without waiting for unique mtime:s")
       pr.add("-j", "--parallel",     "build in parallel",  type: Integer, default: 1, metavar: "N")
       pr.add("",   "--test",         "only run named test", type: [String])

lib/cmdtest/lcs.rb

@@ -0,0 +1,134 @@
+#----------------------------------------------------------------------
+# lcs.rb
+#----------------------------------------------------------------------
+# Copyright 2016 Johan Holmberg.
+#----------------------------------------------------------------------
+# This file is part of "cmdtest".
+#
+# "cmdtest" is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# "cmdtest" is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with "cmdtest".  If not, see <http://www.gnu.org/licenses/>.
+#----------------------------------------------------------------------
+
+module Cmdtest
+
+  class LCS
+    def print()
+      i = @m
+      j = @n
+      while i > 0 || j > 0
+        if @b[i][j] == :XY
+          acc = []
+          while @b[i][j] == :XY
+            acc << @y[j]
+            i -= 1
+            j -= 1
+          end
+          found_xy(acc)
+        elsif i > 0 && (j == 0 || @b[i][j] == :X)
+          acc = []
+          while i > 0 && (j == 0 || @b[i][j] == :X)
+            acc << @x[i]
+            i -= 1
+          end
+          found_x(acc)
+        elsif j > 0 && (i == 0 || @b[i][j] == :Y)
+          acc = []
+          while j > 0 && (i == 0 || @b[i][j] == :Y)
+            acc << @y[j]
+            j -= 1
+          end
+          found_y(acc)
+        else
+          raise "internal error"
+        end
+      end
+    end
+
+    def initialize(x, y)
+      @m = x.size
+      @n = y.size
+      @x = [nil] + x.reverse
+      @y = [nil] + y.reverse
+      @c = Array.new(@m+1) { Array.new(@n+1) }
+      @b = Array.new(@m+1) { Array.new(@n+1) }
+
+      for i in 1..@m
+        @c[i][0] = 0
+      end
+
+      for j in 0..@n
+        @c[0][j] = 0
+      end
+
+      for i in 1..@m
+        for j in 1..@n
+          if @x[i] === @y[j]
+            @c[i][j] = @c[i-1][j-1] + 1
+            @b[i][j] = :XY
+          elsif @c[i-1][j] >= @c[i][j-1]
+            @c[i][j] = @c[i-1][j]
+            @b[i][j] = :X
+          else
+            @c[i][j] = @c[i][j-1]
+            @b[i][j] = :Y
+          end
+        end
+      end
+    end
+
+    def found_xy(arr)
+    end
+
+    def found_x(arr)
+    end
+
+    def found_y(arr)
+    end
+  end
+
+  class DiffLCS < LCS
+    include Enumerable
+
+    def found_x(arr)
+      for e in arr
+        if Regexp === e
+          @arr << "- " + e.inspect
+        else
+          @arr << "- " + e
+        end
+      end
+    end
+
+    def found_y(arr)
+      for e in arr
+        @arr << "+ " + e
+      end
+    end
+
+    def found_xy(arr)
+      for e in arr
+        @arr << "  " + e
+      end
+    end
+
+    def each
+      @arr = []
+      print
+      for e in @arr
+        yield e
+      end
+    end
+  end
+
+
+end

lib/cmdtest/testcase.rb

@@ -23,6 +23,8 @@ require "fileutils"
 require "set"
 require "stringio"
 
+require "cmdtest/lcs"
+
 module Cmdtest
 
   class AssertFailed < RuntimeError ; end
@@ -385,9 +387,15 @@ module Cmdtest
       expected = files.flatten.sort
       #p [:xxx_files, xxx, actual, expected]
       _assert0 actual == expected do
-        _format_output(xxx.to_s.gsub(/_/, " ").gsub(/modified/, "changed"),
-                       actual.inspect + "\n",
-                       expected.inspect + "\n")
+        if @_runner.opts.diff
+          _format_output(xxx.to_s.gsub(/_/, " ").gsub(/modified/, "changed"),
+                         actual,
+                         expected)
+        else
+          _format_output(xxx.to_s.gsub(/_/, " ").gsub(/modified/, "changed"),
+                         actual.inspect + "\n",
+                         expected.inspect + "\n")
+        end
       end
     end
 
@@ -663,17 +671,26 @@ module Cmdtest
       end
     end
 
-    def _indented_lines(prefix, output)
-      case output
-      when Array
-        lines = output
-      when String
-        lines = output.split(/\n/, -1)
+    def _to_lines(str)
+      if Array === str
+        lines = str
+      else
+        lines = str.split(/\n/, -1)
         if lines[-1] == ""
           lines.pop
         elsif ! lines.empty?
           lines[-1] << "[[missing newline]]"
         end
+      end
+      return lines
+    end
+
+    def _indented_lines(prefix, output)
+      case output
+      when Array
+        lines = output
+      when String
+        lines = _to_lines(output)
       when Regexp
         lines = [output]
       else
@@ -696,8 +713,15 @@ module Cmdtest
     def _format_output(error, actual, expected)
       res = ""
       res << "ERROR: #{error}\n"
-      res << _indented_lines("       actual: ", actual)
-      res << _indented_lines("       expect: ", expected)
+      if @_runner.opts.diff && (Array === expected || String === expected)
+        expected_lines = _to_lines(expected)
+        actual_lines = _to_lines(actual)
+        diff = DiffLCS.new(expected_lines, actual_lines)
+        res << _indented_lines("  ", diff.to_a)
+      else
+        res << _indented_lines("       actual: ", actual)
+        res << _indented_lines("       expect: ", expected)
+      end
       return res
     end