### Question:
StringInterpolator { public List<String> interpolateList(@Nullable List<String> templates, VariableProvider provider) { if (templates == null) { return ImmutableList.of(); } Function<String, String> transformer = transformer(provider); return Lists.transform(templates, transformer); }  String interpolate(String template,
                            final Map<String, ?> variables); String interpolate(String template,
                            VariableProvider provider); Set<String> getVariables(String template); Map<String, String> interpolateValues(@Nullable Map<String, String> templates,
                                               VariableProvider provider); List<String> interpolateList(@Nullable List<String> templates,
                                      VariableProvider provider);  }### Answer:
@Test public void testInterpolateList() { List<String> list = ImmutableList.of("This is ${var1}", "This is ${var2}"); List<String> convertedList = ImmutableList.of("This is value1", "This is value2"); assertEquals(convertedList, interpolator.interpolateList(list, provider)); }
@Test public void testInterpolateListNull() { assertEquals(ImmutableList.<String>of(), interpolator.interpolateList(null, provider)); }