Merge #619: Improve instructions for the testing environment

adf0fe2 Add coldcard instructions (Giacomo Caironi)
fa5f389 Add instructions for building the ledger emulator (Giacomo Caironi)

Pull request description:

  Instructions to build the testing environment are not exhaustive. This PR tries to fix this

ACKs for top commit:
  achow101:
    ACK adf0fe2

Tree-SHA512: af43e56b510a836446a15085838475747cb5e4c1813ad59aee3bfaee9ddebeb2706d3d8f5d848f96e4efc480d35c4a99423595c26699e3b3816db456a3f42880

test/README.md

@@ -46,7 +46,7 @@ $ cd work
 In order to build the Trezor emulator, the following packages will need to be installed:
 
 ```
-build-essential curl git python3 python3-pip libsdl2-dev libsdl2-image-dev gcc-arm-none-eabi libnewlib-arm-none-eabi gcc-multilib
+build-essential curl git python3 python3-pip libsdl2-dev libsdl2-image-dev gcc-arm-none-eabi libnewlib-arm-none-eabi gcc-multilib protobuf-compiler clang
 ```
 
 The python packages can be installed with
@@ -277,6 +277,59 @@ $ cp jade/main/qemu/qemu_efuse.bin simulator/
 $ cd ..
 ```
 
+## Ledger emulator
+
+### Dependencies
+
+In order to build the Ledger emulator, the following packages will need to be installed:
+
+```
+cmake gcc-arm-linux-gnueabihf libc6-dev-armhf-cross gdb-multiarch qemu-user-static
+```
+
+The python packages can be installed with
+
+```
+pip install construct flask-restful jsonschema mnemonic pyelftools pillow requests
+```
+
+### Building
+
+Clone the repository:
+
+```
+$ git clone --recursive https://github.com/LedgerHQ/speculos.git
+```
+
+Build the emulator:
+
+```
+$ cmake -Bbuild -H.
+$ make -C build/
+```
+
+## Coldcard emulator
+
+Clone the repository:
+
+```
+git clone --recursive https://github.com/Coldcard/firmware.git
+```
+
+### Dependencies
+
+In order to build the Coldcard emulator, the following packages will need to be installed:
+
+```
+build-essential git python3 python3-pip libudev-dev gcc-arm-none-eabi libffi-dev xterm swig libpcsclite-dev
+```
+You also have to install its python dependencies
+
+```
+pip install -r requirements.txt
+```
+
+
 ## Bitcoin Core
 
 In order to build `bitcoind`, see [Bitcoin Core's build documentation](https://github.com/bitcoin/bitcoin/blob/master/doc/build-unix.md#linux-distribution-specific-instructions) to get all of the dependencies installed and for instructions on how to build.