fix(hana): env var pointing to dbcapi

hana-client + jest need to be persuaded

__tests__/__assets__/hana-jest.config.js

@@ -0,0 +1,36 @@
+// taken straight from
+// https://github.com/facebook/jest/issues/7480#issuecomment-492976544
+// with some minor bugfixes added
+
+const os = require('os')
+const path = require('path')
+
+module.exports = async () => {
+  const extensions = {
+    darwin: 'dylib',
+    linux: 'so',
+    win32: 'dll',
+  }
+
+  // Look for prebuilt binary and DBCAPI based on platform
+  let pb_subdir = null
+  if (process.platform === 'linux') {
+    if (process.arch === 'x64') {
+      pb_subdir = 'linuxx86_64-gcc48'
+    } else if (process.arch.toLowerCase().indexOf('ppc') != -1 && os.endianness() === 'LE') {
+      pb_subdir = 'linuxppc64le-gcc48'
+    } else {
+      pb_subdir = 'linuxppc64-gcc48'
+    }
+  } else if (process.platform === 'win32') {
+    pb_subdir = 'ntamd64-msvc2010'
+  } else if (process.platform === 'darwin') {
+    pb_subdir = 'darwinintel64-xcode7'
+  }
+
+  const modpath = path.dirname(require.resolve('@sap/hana-client/README.md'))
+  const pb_path = path.join(modpath, 'prebuilt', pb_subdir)
+  const dbcapi = process.env['DBCAPI_API_DLL'] || path.join(pb_path, 'libdbcapiHDB.' + extensions[process.platform])
+
+  process.env['DBCAPI_API_DLL'] = dbcapi
+}