From 2a8463e2b8c55623d152673a547e7b5d16c838f4 Mon Sep 17 00:00:00 2001
From: Simon Glass <sjg@chromium.org>
Date: Thu, 30 Apr 2020 15:25:04 -0600
Subject: [PATCH] shell: Extend dummy backend to record for testing

It is useful to run tests which generate shell output and check that it
is correct. Update the existing 'dummy' backend to support this.

It works by retaining the output in a small buffer so that it can be
read and checked by the test.

Signed-off-by: Simon Glass <sjg@chromium.org>
---
 include/shell/shell_dummy.h | 20 ++++++++++++++++++++
 subsys/shell/shell_dummy.c  | 24 ++++++++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/include/shell/shell_dummy.h b/include/shell/shell_dummy.h
index c39eeb88fca..675d4cddfaa 100644
--- a/include/shell/shell_dummy.h
+++ b/include/shell/shell_dummy.h
@@ -1,4 +1,6 @@
 /*
+ * Shell backend used for testing
+ *
  * Copyright (c) 2018 Nordic Semiconductor ASA
  *
  * SPDX-License-Identifier: Apache-2.0
@@ -17,6 +19,12 @@ extern const struct shell_transport_api shell_dummy_transport_api;
 
 struct shell_dummy {
 	bool initialized;
+
+	/** current number of bytes in buffer (0 if no output) */
+	size_t len;
+
+	/** output buffer to collect shell output */
+	char buf[100];
 };
 
 #define SHELL_DUMMY_DEFINE(_name)					\
@@ -37,6 +45,18 @@ struct shell_dummy {
  */
 const struct shell *shell_backend_dummy_get_ptr(void);
 
+/**
+ * @brief Returns the buffered output in the shell and resets the pointer
+ *
+ * The returned data is always followed by a nul character at position *sizep
+ *
+ * @param shell		Shell pointer
+ * @param sizep		Returns size of data in shell buffer
+ * @returns pointer to buffer containing shell output
+ */
+const char *shell_backend_dummy_get_output(const struct shell *shell,
+					   size_t *sizep);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/subsys/shell/shell_dummy.c b/subsys/shell/shell_dummy.c
index a9c4e9ffe69..bb302399634 100644
--- a/subsys/shell/shell_dummy.c
+++ b/subsys/shell/shell_dummy.c
@@ -1,4 +1,6 @@
 /*
+ * Shell backend used for testing
+ *
  * Copyright (c) 2018 Nordic Semiconductor ASA
  *
  * SPDX-License-Identifier: Apache-2.0
@@ -55,13 +57,22 @@ static int write(const struct shell_transport *transport,
 		 const void *data, size_t length, size_t *cnt)
 {
 	struct shell_dummy *sh_dummy = (struct shell_dummy *)transport->ctx;
+	size_t store_cnt;
 
 	if (!sh_dummy->initialized) {
 		*cnt = 0;
 		return -ENODEV;
 	}
 
+	store_cnt = length;
+	if (sh_dummy->len + store_cnt >= sizeof(sh_dummy->buf)) {
+		store_cnt = sizeof(sh_dummy->buf) - sh_dummy->len - 1;
+	}
+	memcpy(sh_dummy->buf + sh_dummy->len, data, store_cnt);
+	sh_dummy->len += store_cnt;
+
 	*cnt = length;
+
 	return 0;
 }
 
@@ -99,3 +110,16 @@ const struct shell *shell_backend_dummy_get_ptr(void)
 {
 	return &shell_dummy;
 }
+
+const char *shell_backend_dummy_get_output(const struct shell *shell,
+					   size_t *sizep)
+{
+	struct shell_dummy *sh_dummy;
+
+	sh_dummy = (struct shell_dummy *)shell->iface->ctx;
+	sh_dummy->buf[sh_dummy->len] = '\0';
+	*sizep = sh_dummy->len;
+	sh_dummy->len = 0;
+
+	return sh_dummy->buf;
+}