diff --git a/Makefile.am b/Makefile.am
index 91d94db078fed136756bf91276818e858b700c24..883f67cc9c6eb6845a473d201649d64f310608b8 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -167,6 +167,7 @@ test_cases = \
 	tests/extensions/metadata/execute.svtest \
 	tests/extensions/metadata/errors.svtest \
 	tests/extensions/mime/errors.svtest \
+	tests/extensions/mime/header.svtest \
 	tests/extensions/mime/execute.svtest \
 	tests/extensions/mime/content-header.svtest \
 	tests/extensions/mime/foreverypart.svtest \
diff --git a/tests/extensions/mime/header.svtest b/tests/extensions/mime/header.svtest
new file mode 100644
index 0000000000000000000000000000000000000000..2683cf455edbaec95a0bde9429cbc78be0f93426
--- /dev/null
+++ b/tests/extensions/mime/header.svtest
@@ -0,0 +1,224 @@
+require "vnd.dovecot.testsuite";
+require "variables";
+require "mime";
+
+/*
+ * Basic functionality
+ */
+
+test_set "message" text:
+From: stephan@example.com
+To: nico@nl.example.com, harry@de.example.com
+Subject: Frobnitzm
+Comments: This is nonsense.
+Keywords: nonsense, strange, testing
+X-Spam: Yes
+
+Test.
+.
+;
+
+test "Basic functionality" {
+	/* Must match */
+	if not header :mime :anychild :contains ["Subject", "Comments"] "Frobnitzm" {
+		test_fail "failed to match header (1)";
+	}
+
+	if not header :mime :anychild :contains ["Subject", "Comments"] "nonsense" {
+		test_fail "failed to match header(2)";
+	}
+
+	if not header :mime :anychild :matches "Keywords" "*, strange, *" {
+		test_fail "failed to match header (3)";
+	}
+
+	if not header :mime :anychild :is "Comments" "This is nonsense." {
+		test_fail "failed to match header (4)";
+	}
+
+	/* Must not match */
+	if header :mime :anychild ["subject", "comments", "keywords"] "idiotic" {
+		test_fail "matched nonsense";
+	}
+
+	/* Match first key */
+	if not header :mime :anychild :contains ["keywords"] ["strange", "snot", "vreemd"] {
+		test_fail "failed to match first key";
+	}
+
+	/* Match second key */
+	if not header :mime :anychild :contains ["keywords"] ["raar", "strange", "vreemd"] {
+		test_fail "failed to match second key";
+	}
+
+	/* Match last key */
+	if not header :mime :anychild :contains ["keywords"] ["raar", "snot", "strange"] {
+		test_fail "failed to match last key";
+	}
+
+	/* First header */
+	if not header :mime :anychild :contains ["keywords", "subject"]
+		["raar", "strange", "vreemd"] {
+		test_fail "failed to match first header";
+	}
+
+	/* Second header */
+	if not header :mime :anychild :contains ["subject", "keywords"]
+		["raar", "strange", "vreemd"] {
+		test_fail "failed to match second header";
+	}
+}
+
+/*
+ * Matching empty key
+ */
+
+test_set "message" text:
+From: stephan@example.org
+To: nico@frop.example.com
+X-Caffeine: C8H10N4O2
+Subject: I need coffee!
+Comments:
+
+Text
+.
+;
+
+test "Matching empty key" {
+	if header :mime :anychild :is "X-Caffeine" "" {
+		test_fail ":is-matched non-empty header with empty string";
+	}
+
+	if not header :mime :anychild :contains "X-Caffeine" "" {
+		test_fail "failed to match existing header with empty string";
+	}
+
+	if not header :mime :anychild :is "comments" "" {
+		test_fail "failed to match empty header :mime :anychild with empty string";
+	}
+
+	if header :mime :anychild :contains "X-Nonsense" "" {
+		test_fail ":contains-matched non-existent header with empty string";
+	}
+}
+
+/*
+ * Ignoring whitespace
+ */
+
+test_set "message" text:
+From: stephan@example.org
+To: nico@frop.example.com
+Subject:         Help
+X-A:     Text
+X-B: Text   
+
+Text
+.
+;
+
+test "Ignoring whitespace" {
+	if not header :mime :anychild :is "x-a" "Text" {
+		if header :mime :anychild :matches "x-a" "*" {
+			set "header" "${1}"; 
+		}
+		test_fail "header :mime :anychild test does not strip leading whitespace (header=`${header}`)";
+	}
+
+	if not header :mime :anychild :is "x-b" "Text" {
+		if header :mime :anychild :matches "x-b" "*" {
+			set "header" "${1}"; 
+		}
+		test_fail "header :mime :anychild test does not strip trailing whitespace (header=`${header}`)";
+	}
+
+	if not header :mime :anychild :is "subject" "Help" {
+		if header :mime :anychild :matches "subject" "*" {
+			set "header" "${1}"; 
+		}
+		test_fail "header :mime :anychild test does not strip both leading and trailing whitespace (header=`${header}`)";
+	}
+}
+
+/*
+ * Absent or empty header
+ */
+
+test_set "message" text:
+From: stephan@example.org
+To: nico@frop.example.com
+CC: harry@nonsense.ex
+Subject:
+Comments:
+
+Text
+.
+;
+
+test "Absent or empty header" {
+	if not header :mime :anychild :matches "Cc" "?*" {
+		test_fail "CC header is not absent or empty";
+	}
+
+	if header :mime :anychild :matches "Subject" "?*" {
+		test_fail "Subject header is empty, but matched otherwise";
+	}
+
+	if header :mime :anychild :matches "Comment" "?*" {
+		test_fail "Comment header is empty, but matched otherwise";
+	}
+}
+
+/*
+ * Invalid header name
+ */
+
+test_set "message" text:
+From: stephan@example.org
+To: nico@frop.example.com
+Subject: Valid message
+X-Multiline: This is a multi-line
+ header body, which should be
+ unfolded correctly.
+
+Text
+.
+;
+
+test "Invalid header name" {
+	if header :mime :anychild :contains "subject:" "" {
+		test_fail "matched invalid header name";
+	}
+
+	if header :mime :anychild :contains "to!" "" {
+		test_fail "matched invalid header name";
+	}
+}
+
+/*
+ * Folded headers
+ */
+
+/* "Header lines are unfolded as described in [RFC 2822] section 2.2.3.
+ *  ...
+ * "
+ */
+
+test_set "message" text:
+From: stephan@example.org
+To: nico@frop.example.com
+Subject: Not enough space on a line!
+X-Multiline: This is a multi-line
+ header body, which should be
+ unfolded correctly.
+
+Text
+.
+;
+
+test "Folded header" {
+	if not header :mime :anychild :is "x-multiline"
+		"This is a multi-line header body, which should be unfolded correctly." {
+		test_fail "failed to properly unfold folded header.";
+	}
+}