Add unit tests for bcd2char and char2bcd conversion

Sounds stupid, but we actually didn't support hex nibbles in one of
the two directions of the conversion, so let's make sure we test for
this.

Change-Id: I8445da54cc4f9b1cd64f286c2b238f4f7c87accb
diff --git a/tests/utils/utils_test.ok b/tests/utils/utils_test.ok
index 45156f7..33a185b 100644
--- a/tests/utils/utils_test.ok
+++ b/tests/utils/utils_test.ok
@@ -57,3 +57,21 @@
 26: pass str='BeadedBeeAced1EbbedDefacedFacade' min=32 max=32 even=1 expect=valid
 27: pass str='C01ffedC1cadaeAc1d1f1edAcac1aB0a' min=32 max=32 even=0 expect=valid
 28: pass str='DeafBeddedBabeAcceededFadedDecaff' min=32 max=32 even=0 expect=invalid
+
+Testing BCD conversion
+	val=0x0, expected=0, found=0
+	val=0x1, expected=1, found=1
+	val=0x2, expected=2, found=2
+	val=0x3, expected=3, found=3
+	val=0x4, expected=4, found=4
+	val=0x5, expected=5, found=5
+	val=0x6, expected=6, found=6
+	val=0x7, expected=7, found=7
+	val=0x8, expected=8, found=8
+	val=0x9, expected=9, found=9
+	val=0xa, expected=A, found=A
+	val=0xb, expected=B, found=B
+	val=0xc, expected=C, found=C
+	val=0xd, expected=D, found=D
+	val=0xe, expected=E, found=E
+	val=0xf, expected=F, found=F