diff --git a/Makefile b/Makefile
index 03429fb..54c2073 100644
--- a/Makefile
+++ b/Makefile
@@ -79,6 +79,11 @@ distclean: clean
 	$(E) "[REM] $(BINDIR)"
 	$(Q) $(RMR) $(BINDIR)
 
+.PHONY: check
+check:
+	$(E) "[CHK] Not implemented."
+	$(Q) true
+
 .PHONY: listen
 listen: opt/tools/serial-listen
 	$(E) "[RUN] $<"
diff --git a/docs/README.md b/docs/README.md
index 3c497f1..4434727 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -36,6 +36,13 @@ of these commands:
     make clean
     make distclean
 
+Isolated unit tests allow you to verify all testable
+components are behaving as expected. Please note that most
+tests will be added later down the road, when the project
+has reached a more mature state.
+
+    make check
+
 You can listen on the serial debug interface by running
 the command below. This will also initialize all optional
 submodules on first invocation.
@@ -64,8 +71,8 @@ Issue the SET command to update the target settings:
 
 Settings are stored in EEPROM and are persistent until a new
 SET command is issued. Keywords are not case-sensitive. Both
-arguments may contain a decimal point followed by a sequence
-of digits.
+arguments may contain an optional decimal point followed by
+a sequence of digits.
 
 ### Webinterface Example
 
diff --git a/tests/bus/test-i2c.c b/tests/bus/test-i2c.c
new file mode 100644
index 0000000..68036ed
--- /dev/null
+++ b/tests/bus/test-i2c.c
@@ -0,0 +1 @@
+static void *TODO;
diff --git a/tests/bus/test-mosfet.c b/tests/bus/test-mosfet.c
new file mode 100644
index 0000000..68036ed
--- /dev/null
+++ b/tests/bus/test-mosfet.c
@@ -0,0 +1 @@
+static void *TODO;
diff --git a/tests/bus/test-pwm.c b/tests/bus/test-pwm.c
new file mode 100644
index 0000000..68036ed
--- /dev/null
+++ b/tests/bus/test-pwm.c
@@ -0,0 +1 @@
+static void *TODO;
diff --git a/tests/bus/test-usart.c b/tests/bus/test-usart.c
new file mode 100644
index 0000000..68036ed
--- /dev/null
+++ b/tests/bus/test-usart.c
@@ -0,0 +1 @@
+static void *TODO;
diff --git a/tests/common/test-math.c b/tests/common/test-math.c
new file mode 100644
index 0000000..68036ed
--- /dev/null
+++ b/tests/common/test-math.c
@@ -0,0 +1 @@
+static void *TODO;
diff --git a/tests/common/test-memory.c b/tests/common/test-memory.c
new file mode 100644
index 0000000..68036ed
--- /dev/null
+++ b/tests/common/test-memory.c
@@ -0,0 +1 @@
+static void *TODO;
diff --git a/tests/common/test-parser.c b/tests/common/test-parser.c
new file mode 100644
index 0000000..68036ed
--- /dev/null
+++ b/tests/common/test-parser.c
@@ -0,0 +1 @@
+static void *TODO;
diff --git a/tests/main.c b/tests/main.c
new file mode 100644
index 0000000..b4fa8fe
--- /dev/null
+++ b/tests/main.c
@@ -0,0 +1,10 @@
+// TODO: Automatic unit-testing.
+
+int main(void)
+{
+	// 1. Write unit-tests.
+	// 2. Run them.
+	// 3. Profit!
+
+	return 0;
+}