unit tests: add tests for kdump_get_conf_val in kdump-lib-initramfs.sh

kdump_get_conf_val allows to retrieves config value defined in
kdump.conf and it also supports sed regex like
"ext[234]\|xfs\|btrfs\|minix\|raw\|nfs\|ssh".

Reviewed-by: Philipp Rudo <prudo@redhat.com>
Signed-off-by: Coiby Xu <coxu@redhat.com>

spec/kdump-lib-initramfs_spec.sh

@@ -0,0 +1,41 @@
+#!/bin/bash
+Describe 'kdump-lib-initramfs'
+	Include ./kdump-lib-initramfs.sh
+
+	Describe 'Test kdump_get_conf_val'
+		KDUMP_CONFIG_FILE=/tmp/kdump_shellspec_test.conf
+		kdump_config() {
+			%text
+			#|default shell
+			#|nfs my.server.com:/export/tmp # trailing comment
+			#|		failure_action	 shell
+			#|dracut_args --omit-drivers "cfg80211 snd" --add-drivers "ext2 ext3"
+			#|sshkey /root/.ssh/kdump_id_rsa
+			#|ssh user@my.server.com
+		}
+		kdump_config >$KDUMP_CONFIG_FILE
+		Context 'Given different cases'
+			# Test the following cases:
+			#  - there is trailing comment
+			#  - there is space before the parameter
+			#  - complicate value for dracut_args
+			#  - Given two parameters, retrive one parameter that has value specified
+			#  - Given two parameters (in reverse order), retrive one parameter that has value specified
+			Parameters
+				"#1" nfs my.server.com:/export/tmp
+				"#2" ssh user@my.server.com
+				"#3" failure_action shell
+				"#4" dracut_args '--omit-drivers "cfg80211 snd" --add-drivers "ext2 ext3"'
+				"#5" 'ssh\|aaa' user@my.server.com
+				"#6" 'aaa\|ssh' user@my.server.com
+			End
+
+			It 'should handle all cases correctly'
+				When call kdump_get_conf_val "$2"
+				The output should equal "$3"
+			End
+		End
+
+	End
+
+End