Add more test to cover more use cases for G115 rule

Change-Id: Icb60fe14ae12439c1ee0e507a407a23ce4c64c85
Signed-off-by: Cosmin Cojocar <ccojocar@google.com>

testutils/g115_samples.go

@@ -176,6 +176,36 @@ func main() {
 		`
 package main
 
+import (
+	"fmt"
+)
+
+func main() {
+    var a byte = '\xff'
+    b := int64(a)
+    fmt.Println(b)
+}
+	`,
+	}, 0, gosec.NewConfig()},
+	{[]string{
+		`
+package main
+
+import (
+	"fmt"
+)
+
+func main() {
+    var a int8 = -1
+    b := int64(a)
+    fmt.Println(b)
+}
+	`,
+	}, 0, gosec.NewConfig()},
+	{[]string{
+		`
+package main
+
 import (
 	"fmt"
 	"math"
@@ -187,6 +217,21 @@ func main() {
     var a uint = math.MaxUint
     b := CustomType(a)
     fmt.Println(b)
+}
+	`,
+	}, 1, gosec.NewConfig()},
+	{[]string{
+		`
+package main
+
+import (
+	"fmt"
+)
+
+func main() {
+    a := []int{1,2,3}
+    b := uint32(len(a))
+    fmt.Println(b)
 }
 	`,
 	}, 1, gosec.NewConfig()},