Fix travis integration

Makefile

@@ -2,14 +2,17 @@ TMP=tmp
 PS_VERSION=6.1.0
 POSH_GIT_VERSION=v1.0.0-beta3
 
-.PHONY: clean test
+.PHONY: clean clean-test test
 
 test: $(TMP)/powershell/pwsh $(TMP)/posh-git/README.md
 	./git-prompt-test.sh
 
 clean:
 	rm -rf $(TMP)
 
+clean-test:
+	rm -rf $(TMP)/test-scratch
+
 $(TMP):
 	mkdir -p $@
 

git-prompt-test.sh

@@ -1,12 +1,25 @@
 #!/usr/bin/env bash
 
-readonly PS=$(realpath tmp/powershell/pwsh)
-readonly SRC_DIR=$(realpath .)
-readonly POSH_GIT_DIR=$(realpath tmp/posh-git)
-readonly TEST_SCRATCH_DIR=$(realpath tmp/test-scratch)
+set -e
+
+readonly PS=$(readlink -f tmp/powershell/pwsh)
+readonly SRC_DIR=$(readlink -f .)
+readonly POSH_GIT_DIR=$(readlink -f tmp/posh-git)
+readonly TEST_SCRATCH_DIR=$(readlink -f tmp/test-scratch)
+
+DIFF_FLAGS=
+case "$-i" in
+  *i*) if [ -z "$TRAVIS" ]; then
+         DIFF_FLAGS=--color=auto 
+       fi ;;
+  *)   ;;
+esac
+readonly DIFF_FLAGS
 
 mkdir -p $TEST_SCRATCH_DIR
 
+set +e
+
 # Captures the posh command prompt for posh-git-sh and posh-git.
 #
 # Input:
@@ -70,7 +83,7 @@ test_poshes_ignoring_color() {
   local actual_out=$actual-nocolor
   strip_ansi_colors "$expected" > "$expected_out"
   strip_ansi_colors "$actual" > "$actual_out"
-  diff -u --color=always --label="$expected_out" "$expected_out" --label="$actual_out" "$actual_out"
+  diff -u --label="$expected_out" "$expected_out" --label="$actual_out" "$actual_out" $DIFF_FLAGS
 }
 
 PASSING=0