test-cases: Fix hang when computing the root package

The code that computed the root package of all packages under test was
buggy.  Depending on the order of the packages supplied to test-cases,
it was possible to enter an endless loop.  This PR fixes the issue.

Fixes #307

Signed-off-by: Mark Ryan <[email protected]>

Author: Mark Ryan

test-cases/test-cases.go

@@ -424,27 +424,30 @@ func generateHTMLReport(tests []*PackageTests) error {
 }
 
 func findCommonPrefix(tests []*PackageTests) string {
-	if len(tests) == 0 {
-		return ""
-	}
-
-	pkgName := tests[0].Name
-OUTER:
-	for {
+	for j := range tests {
+		pkgName := tests[j].Name
 		index := strings.LastIndex(pkgName, "/")
 		if index == -1 {
 			return ""
 		}
-		pkgName := pkgName[:index+1]
+		pkgRoot := pkgName[:index+1]
 
 		var i int
-		for i = 1; i < len(tests); i++ {
-			if !strings.HasPrefix(tests[i].Name, pkgName) {
-				continue OUTER
+		for i = 0; i < len(tests); i++ {
+			if i == j {
+				continue
+			}
+			if !strings.HasPrefix(tests[i].Name, pkgRoot) {
+				break
 			}
 		}
-		return pkgName
+
+		if i == len(tests) {
+			return pkgRoot
+		}
 	}
+
+	return ""
 }
 
 func dumpFailedTestOutput(prefix string, tests []*PackageTests, colourOn, colourOff string) {