From e35b4b66cc57e2551f52df155cf3d3f4e2c67280 Mon Sep 17 00:00:00 2001
From: Russ Ross <russ@russross.com>
Date: Sun, 3 Jul 2011 10:51:07 -0600
Subject: [PATCH] bounds checking stress tests

---
 block_test.go      | 23 ++++++++++++++++++++--
 inline_test.go     | 23 ++++++++++++++++++++--
 markdown.go        |  6 ++++++
 upskirtref_test.go | 49 ++++++++++++++++++++++++++++++++--------------
 4 files changed, 82 insertions(+), 19 deletions(-)

diff --git a/block_test.go b/block_test.go
index 888841e..dac78da 100644
--- a/block_test.go
+++ b/block_test.go
@@ -27,13 +27,32 @@ func runMarkdownBlock(input string, extensions int) string {
 }
 
 func doTestsBlock(t *testing.T, tests []string, extensions int) {
+	// catch and report panics
+	var candidate string
+	defer func() {
+		if err := recover(); err != nil {
+			t.Errorf("\npanic while processing [%#v]\n", candidate)
+		}
+	}()
+
 	for i := 0; i+1 < len(tests); i += 2 {
 		input := tests[i]
+		candidate = input
 		expected := tests[i+1]
-		actual := runMarkdownBlock(input, extensions)
+		actual := runMarkdownBlock(candidate, extensions)
 		if actual != expected {
 			t.Errorf("\nInput   [%#v]\nExpected[%#v]\nActual  [%#v]",
-				input, expected, actual)
+				candidate, expected, actual)
+		}
+
+		// now test every substring to stress test bounds checking
+		if !testing.Short() {
+			for start := 0; start < len(input); start++ {
+				for end := start + 1; end <= len(input); end++ {
+					candidate = input[start:end]
+					_ = runMarkdownBlock(candidate, extensions)
+				}
+			}
 		}
 	}
 }
diff --git a/inline_test.go b/inline_test.go
index 7995794..0ddc0a7 100644
--- a/inline_test.go
+++ b/inline_test.go
@@ -31,13 +31,32 @@ func runMarkdownInline(input string) string {
 }
 
 func doTestsInline(t *testing.T, tests []string) {
+	// catch and report panics
+	var candidate string
+	defer func() {
+		if err := recover(); err != nil {
+			t.Errorf("\npanic while processing [%#v]\n", candidate)
+		}
+	}()
+
 	for i := 0; i+1 < len(tests); i += 2 {
 		input := tests[i]
+		candidate = input
 		expected := tests[i+1]
-		actual := runMarkdownInline(input)
+		actual := runMarkdownInline(candidate)
 		if actual != expected {
 			t.Errorf("\nInput   [%#v]\nExpected[%#v]\nActual  [%#v]",
-				input, expected, actual)
+				candidate, expected, actual)
+		}
+
+		// now test every substring to stress test bounds checking
+		if !testing.Short() {
+			for start := 0; start < len(input); start++ {
+				for end := start + 1; end <= len(input); end++ {
+					candidate = input[start:end]
+					_ = runMarkdownInline(candidate)
+				}
+			}
 		}
 	}
 }
diff --git a/markdown.go b/markdown.go
index 0bccdd8..46d60db 100644
--- a/markdown.go
+++ b/markdown.go
@@ -270,6 +270,12 @@ func firstPass(parser *Parser, input []byte) []byte {
 			beg = end
 		}
 	}
+
+	// empty input?
+	if out.Len() == 0 {
+		out.WriteByte('\n')
+	}
+
 	return out.Bytes()
 }
 
diff --git a/upskirtref_test.go b/upskirtref_test.go
index 2dedc66..47e6c75 100644
--- a/upskirtref_test.go
+++ b/upskirtref_test.go
@@ -25,27 +25,46 @@ func runMarkdownReference(input string) string {
 }
 
 func doTestsReference(t *testing.T, files []string) {
-	for _, basename := range files {
-		fn := filepath.Join("upskirtref", basename+".text")
-		actualdata, err := ioutil.ReadFile(fn)
-		if err != nil {
-			t.Errorf("Couldn't open '%s', error: %v\n", fn, err)
-			continue
-		}
-		fn = filepath.Join("upskirtref", basename+".html")
-		expecteddata, err := ioutil.ReadFile(fn)
-		if err != nil {
-			t.Errorf("Couldn't open '%s', error: %v\n", fn, err)
-			continue
+	// catch and report panics
+	var candidate string
+	defer func() {
+		if err := recover(); err != nil {
+			t.Errorf("\npanic while processing [%#v]\n", candidate)
 		}
+	}()
 
-		actual := string(actualdata)
-		actual = string(runMarkdownReference(actual))
-		expected := string(expecteddata)
+	for _, basename := range files {
+		filename := filepath.Join("upskirtref", basename+".text")
+		inputBytes, err := ioutil.ReadFile(filename)
+		if err != nil {
+			t.Errorf("Couldn't open '%s', error: %v\n", filename, err)
+			continue
+		}
+		input := string(inputBytes)
+
+		filename = filepath.Join("upskirtref", basename+".html")
+		expectedBytes, err := ioutil.ReadFile(filename)
+		if err != nil {
+			t.Errorf("Couldn't open '%s', error: %v\n", filename, err)
+			continue
+		}
+		expected := string(expectedBytes)
+
+		actual := string(runMarkdownReference(input))
 		if actual != expected {
 			t.Errorf("\n    [%#v]\nExpected[%#v]\nActual  [%#v]",
 				basename+".text", expected, actual)
 		}
+
+		// now test every substring of every input to check for
+		// bounds checking
+		if !testing.Short() {
+			start := 0
+			for end := start + 1; end <= len(input); end++ {
+				candidate = input[start:end]
+				_ = runMarkdownReference(candidate)
+			}
+		}
 	}
 }