# Solidity-Coverage API
Solidity-coverage tracks which lines are hit as your tests run by instrumenting the contracts with special solidity statements and detecting their execution in a coverage-enabled EVM.
As such, the API spans the full set of tasks typically required to run a solidity test suite. The
table below shows how its core methods relate to the stages of a test run:
| Test Stage | API Method | Description |
|---------------|--------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| compilation | `instrument` | A **pre-compilation** step: Rewrites contracts and generates an instrumentation data map. |
| client launch | `ganache` | A **substitute** step: Launches a ganache client with coverage collection enabled in its VM. As the client runs it will mark line/branch hits on the instrumentation data map. |
| test | `report` | A **post-test** step: Generates a coverage report from the data collected by the VM after tests complete. |
| exit | `finish` | A **substitute** step: Shuts client down |
[3]: https://github.com/gotwarlost/istanbul
**Additional Resources:**
+ the library includes [file system utilities](#Utils) for managing the
disposable set of contracts/artifacts which coverage must use in lieu of the 'real' (uninstrumented)
contracts.
+ there are two complete [coverage tool/plugin implementations][5] (for Buidler and Truffle)
which can be used as sources if you're building something similar.
[5]: https://github.com/sc-forks/solidity-coverage/tree/master/plugins
# Table of Contents
- [API Methods](#api)
* [constructor](#constructor)
* [instrument](#instrument)
* [ganache](#ganache)
* [report](#report)
* [finish](#finish)
* [getInstrumentationData](#getinstrumentationdata)
* [setInstrumentationData](#setinstrumentationdata)
- [Utils Methods](#utils)
* [loadSolcoverJS](#loadsolcoverjs)
* [assembleFiles](#assemblefiles)
* [getTempLocations](#gettemplocations)
* [setupTempFolders](#setuptempfolders)
* [save](#save)
* [finish](#finish-1)
# API
**Example**
```javascript
const CoverageAPI = require("solidity-coverage/api");
const api = new CoverageAPI(options);
```
## constructor
Creates a coverage API instance. Configurable.
**Parameters**
- `options` **Object** : API options
| Option | Type | Default | Description |
| ------ | ---- | ------- | ----------- |
| port | *Number* | 8555 | Port to launch client on |
| silent | *Boolean* | false | Suppress logging output |
| client | *Object* | `require("ganache-core")` | JS Ethereum client |
| providerOptions | *Object* | `{ }` | [ganache-core options][1] |
| skipFiles | *Array* | `[]` | Array of contracts or folders (with paths expressed relative to the `contracts` directory) that should be skipped when doing instrumentation. |
| istanbulFolder | *String* | `./coverage` | Folder location for Istanbul coverage reports. |
| istanbulReporter | *Array* | `['html', 'lcov', 'text', 'json']` | [Istanbul coverage reporters][2] |
[1]: https://github.com/trufflesuite/ganache-core#options
[2]: https://istanbul.js.org/docs/advanced/alternative-reporters/
--------------
## instrument
Instruments a set of sources to prepare them for compilation.
:warning: **Important:** Instrumented sources must be compiled with **solc optimization OFF** :warning:
**Parameters**
- `contracts` **Object[]**: Array of solidity sources and their paths
Returns **Object[]** in the same format as the `contracts` param, but with sources instrumented.
**Example**
```javascript
const contracts = [{
source: "contract Simple { uint x = 5; }",
canonicalPath: "/Users/user/project/contracts/Simple.sol",
relativePath: "Simple.sol" // Optional, used for pretty printing.
},...]
const instrumented = api.instrument(contracts)
```
--------------
## ganache
Enables coverage data collection on an in-process ganache server. By default, this method launches
the server, begins listening on the port specified in the [config](#constructor) (or 8555 if unspecified), and
returns a url string. When `autoLaunchServer` is false, method returns `ganache.server` so you can control
the `server.listen` invocation yourself.
**Parameters**
- `client` **Object**: (*Optional*) ganache module
- `autoLaunchServer` **Boolean**: (*Optional*)
Returns **Promise** Address of server to connect to, or initialized, unlaunched server
**Example**
```javascript
const client = require('ganache-cli');
const api = new CoverageAPI( { client: client } );
const address = await api.ganache();
> http://127.0.0.1:8555
// Alternatively...
const server = await api.ganache(client, false);
await pify(server.listen()(8545));
```
--------------
## report
Generates coverage report using IstanbulJS
**Parameters**
- `istanbulFolder` **String**: (*Optional*) path to folder Istanbul will deposit coverage reports in.
Returns **Promise**
**Example**
```javascript
await api.report('./coverage_4A3cd2b'); // Default folder name is 'coverage'
```
-------------
## finish
Shuts down coverage-enabled ganache server instance
Returns **Promise**
**Example**
```javascript
const client = require('ganache-cli');
await api.ganache(client); // Server listening...
await api.finish(); // Server shut down.
```
-------------
## getInstrumentationData
Returns a copy of the hit map created during instrumentation. Useful if you'd like to delegate
coverage collection to multiple processes.
Returns **Object** instrumentation data;
**Example**
```javascript
const instrumented = api.instrument(contracts);
const data = api.getInstrumentationData();
save(data); // Pseudo-code
```
-------------
## setInstrumentationData
Sets the hit map object generated during instrumentation. Useful if you'd like
to collect or convert data to coverage for an instrumentation which was generated
in a different process.
**Example**
```javascript
const data = load(data); // Pseudo-code
api.setIntrumentationData(data);
// Client will collect data for the loaded map
const address = await api.ganache(client);
// Or to `report` instrumentation data which was collected in a different process.
const data = load(data); // Pseudo-code
api.setInstrumentationData(data);
api.report();
```
----------------------------------------------------------------------------------------------------
# Utils
```javascript
const utils = require('solidity-coverage/utils');
```
Many of the utils methods take a `config` object param which
defines the absolute paths to your project root and contracts directory.
**Example**
```javascript
const config = {
workingDir: process.cwd(),
contractsDir: path.join(process.cwd(), 'contracts'),
}
```
-------------
## loadSolcoverJS
Loads `.solcoverjs`. Users may specify [options][7] in a `.solcover.js` config file which your
application needs to consume.
**Parameters**
- `config` **Object**: [See *config* above](#Utils)
Returns **Object** Normalized coverage config
**Example**
```javascript
const solcoverJS = utils.loadSolcoverJS(config);
const api = new CoverageAPI(solcoverJS);
```
[7]: https://github.com/sc-forks/solidity-coverage/tree/master#config-options
-------------
## assembleFiles
Loads contracts from the filesystem in a format that can be passed directly to the
[api.instrument](#instrument) method. Filters by an optional `skipFiles` parameter.
**Parameters**
- `config` **Object**: [See *config* above](#Utils)
- `skipFiles` **String[]**: (*Optional*) Array of files or folders to skip
[See API *constructor*](#constructor)
Returns **Object** with `targets` and `skipped` keys. These are Object arrays of contract sources
and paths.
**Example**
```javascript
const {
targets,
skipped
} = utils.assembleFiles(config, ['Migrations.sol'])
const instrumented = api.instrument(contracts);
```
--------------
## getTempLocations
Returns a pair of canonically named temporary directory paths for contracts
and artifacts. Instrumented assets can be compiled from and written to these so the unit tests can
use them as sources.
**Parameters**
- `config` **Object**: [See *config* above](#Utils)
Returns **Object** with two absolute paths to disposable folders, `tempContractsDir`, `tempArtifactsDir`.
These directories are named `.coverage_contracts` and `.coverage_artifacts`.
**Example**
```javascript
const {
tempContractsDir,
tempArtifactsDir
} = utils.getTempLocations(config)
utils.setupTempFolders(config, tempContractsDir, tempArtifactsDir)
// Later, you can call `utils.finish` to delete these...
utils.finish(config, api)
```
----------
## setupTempFolders
Creates temporary directories to store instrumented contracts and their compilation artifacts in.
**Parameters**
- `config` **Object**: [See *config* above](#Utils)
- `tempContractsDir` **String**: absolute path to temporary contracts directory
- `tempArtifactsDir` **String**: absolute path to temporary artifacts directory
**Example**
```javascript
const {
tempContractsDir,
tempArtifactsDir
} = utils.getTempLocations(config)
utils.setupTempFolders(config, tempContractsDir, tempArtifactsDir);
```
-------------
## save
Writes an array of instrumented sources in the object format returned by
[api.instrument](#instrument) to a temporary directory.
**Parameters**
- `contracts` **Object[]**: array of contracts & paths generated by [api.instrument](#instrument)
- `originalDir` **String**: absolute path to original contracts directory
- `tempDir` **String**: absolute path to temp contracts directory (the destination of the save)
**Example**
```javascript
const {
tempContractsDir,
tempArtifactsDir
} = utils.getTempLocations(config)
utils.setupTempFolders(config, tempContractsDir, tempArtifactsDir);
const instrumented = api.instrument(contracts);
utils.save(instrumented, config.contractsDir, tempContractsDir);
```
-------------
## finish
Deletes temporary folders and shuts the ganache server down. Is tolerant - if folders or ganache
server don't exist it will return silently.
**Parameters**
- `config` **Object**: [See *config* above](#Utils)
- `api` **Object**: (*Optional*) coverage api instance whose own `finish` method will be called
Returns **Promise**
**Example**
```javascript
await utils.finish(config, api);
```