diff --git a/parser/test-common.go b/parser/test-common.go
index 80ee2fd..d16e35f 100644
--- a/parser/test-common.go
+++ b/parser/test-common.go
@@ -1,78 +1,13 @@
 package parser
 
-import "io"
 import "os"
-import "strings"
 import "testing"
 import "path/filepath"
+import "git.tebibyte.media/arf/arf/testCommon"
 
 func checkTree (modulePath string, skim bool, correct string, test *testing.T) {
 	cwd, _ := os.Getwd()
 	modulePath = filepath.Join(cwd, modulePath)
 	tree, err := Fetch(modulePath, skim)
-	
-	treeString := tree.ToString(0)
-	treeRunes  := []rune(treeString)
-	
-	test.Log("CORRECT TREE:")
-	logWithLineNumbers(correct, test)
-	test.Log("WHAT WAS PARSED:")
-	logWithLineNumbers(treeString, test)
-	
-	if err != io.EOF && err != nil {
-		test.Log("returned error:")
-		test.Log(err.Error())
-		test.Fail()
-		return
-	}
-
-	equal  := true
-	line   := 0
-	column := 0
-
-	for index, correctChar := range correct {
-		if index >= len(treeRunes) {			
-			test.Log (
-				"parsed is too short at line", line + 1,
-				"col", column + 1)
-			test.Fail()
-			return
-		}
-		
-		if correctChar != treeRunes[index] {		
-			test.Log (
-				"trees not equal at line", line + 1,
-				"col", column + 1)
-			test.Log("correct: [" + string(correctChar) + "]")
-			test.Log("got:     [" + string(treeRunes[index]) + "]")
-			test.Fail()
-			return
-		}
-
-		if correctChar == '\n' {
-			line ++
-			column = 0
-		} else {
-			column ++
-		}
-	}
-	
-	if len(treeString) > len(correct) {
-		test.Log("parsed is too long")
-		test.Fail()
-		return
-	}
-
-	if !equal {
-		return
-	}
-}
-
-func logWithLineNumbers (bigString string, test *testing.T) {
-	lines := strings.Split (
-		strings.Replace(bigString, "\t", "        ", -1), "\n")
-
-	for index, line := range lines {
-		test.Logf("%3d | %s", index + 1, line)
-	}
+	testCommon.CheckStrings(test, tree, err, correct)
 }
diff --git a/testCommon/test-common.go b/testCommon/test-common.go
new file mode 100644
index 0000000..9d3ad4e
--- /dev/null
+++ b/testCommon/test-common.go
@@ -0,0 +1,91 @@
+package testCommon
+
+import "io"
+import "strings"
+import "testing"
+
+// Stringable encompasses any type that can be converted into a string, given
+// an indentation level.
+type Stringable interface {
+	ToString (indent int) (output string)
+}
+
+// CheckStrings takes in an error, a result value that is able to provide a
+// string, and a correct string to check the result value's string against, and
+// a test pointer. This function will detect the presence of an error, or
+// differences in the result string and the correct string, and fail the test
+// if needed. It also provides detailed output logs to facilitate the correction
+// of test failues.
+func CheckStrings (
+	test    *testing.T,
+	result  Stringable,
+	err     error,
+	correct string,
+) {
+	treeString := result.ToString(0)
+	treeRunes  := []rune(treeString)
+	
+	test.Log("CORRECT:")
+	logWithLineNumbers(correct, test)
+	test.Log("RESULT:")
+	logWithLineNumbers(treeString, test)
+	
+	if err != io.EOF && err != nil {
+		test.Log("returned error:")
+		test.Log(err.Error())
+		test.Fail()
+		return
+	}
+
+	equal  := true
+	line   := 0
+	column := 0
+
+	for index, correctChar := range correct {
+		if index >= len(treeRunes) {			
+			test.Log (
+				"result is too short at line", line + 1,
+				"col", column + 1)
+			test.Fail()
+			return
+		}
+		
+		if correctChar != treeRunes[index] {		
+			test.Log (
+				"strings not equal at line", line + 1,
+				"col", column + 1)
+			test.Log("correct: [" + string(correctChar) + "]")
+			test.Log("got:     [" + string(treeRunes[index]) + "]")
+			test.Fail()
+			return
+		}
+
+		if correctChar == '\n' {
+			line ++
+			column = 0
+		} else {
+			column ++
+		}
+	}
+	
+	if len(treeString) > len(correct) {
+		test.Log("result is too long")
+		test.Fail()
+		return
+	}
+
+	if !equal {
+		return
+	}
+}
+
+// logWithLineNumbers logs a multi-line, indented string with line numbers. It
+// also converts all tabs to spaces for consistent indentation.
+func logWithLineNumbers (bigString string, test *testing.T) {
+	lines := strings.Split (
+		strings.Replace(bigString, "\t", "        ", -1), "\n")
+
+	for index, line := range lines {
+		test.Logf("%3d | %s", index + 1, line)
+	}
+}