diff --git a/e2e/assets/counter_as/dfx.json b/e2e/assets/counter_as/dfx.json
deleted file mode 100644
index 4c088c7203..0000000000
--- a/e2e/assets/counter_as/dfx.json
+++ /dev/null
@@ -1,21 +0,0 @@
-{
-  "// TODO": "Replace this file with `dfx config`.",
-  "version": 1,
-  "dfx": "0.3.0-local-debug",
-  "canisters": {
-    "counter": {
-      "main": "counter.as",
-      "canister_id": 42
-    }
-  },
-  "defaults": {
-    "build": {
-      "output": "build/"
-    },
-    "start": {
-      "port": 8000,
-      "address": "127.0.0.1",
-      "serve_root": "app/"
-    }
-  }
-}
diff --git a/e2e/assets/counter_as/patch.bash b/e2e/assets/counter_as/patch.bash
new file mode 100644
index 0000000000..97cac3c4b3
--- /dev/null
+++ b/e2e/assets/counter_as/patch.bash
@@ -0,0 +1 @@
+dfx config canisters/hello/main counter.as
diff --git a/e2e/assets/counter_wat/dfx.json b/e2e/assets/counter_wat/dfx.json
deleted file mode 100644
index 178547bcaa..0000000000
--- a/e2e/assets/counter_wat/dfx.json
+++ /dev/null
@@ -1,21 +0,0 @@
-{
-  "// TODO": "Replace this file with `dfx config`.",
-  "version": 1,
-  "dfx": "0.3.0-local-debug",
-  "canisters": {
-    "hello": {
-      "main": "counter.wat",
-      "canister_id": 42
-    }
-  },
-  "defaults": {
-    "build": {
-      "output": "build/"
-    },
-    "start": {
-      "port": 8000,
-      "address": "127.0.0.1",
-      "serve_root": "app/"
-    }
-  }
-}
diff --git a/e2e/assets/greet_as/dfx.json b/e2e/assets/greet_as/dfx.json
deleted file mode 100644
index 4a70b01d4d..0000000000
--- a/e2e/assets/greet_as/dfx.json
+++ /dev/null
@@ -1,21 +0,0 @@
-{
-  "// TODO": "Replace this file with `dfx config`.",
-  "version": 1,
-  "dfx": "0.3.0-local-debug",
-  "canisters": {
-    "greet": {
-      "main": "greet.as",
-      "canister_id": 42
-    }
-  },
-  "defaults": {
-    "build": {
-      "output": "build/"
-    },
-    "start": {
-      "port": 8000,
-      "address": "127.0.0.1",
-      "serve_root": "app/"
-    }
-  }
-}
diff --git a/e2e/assets/greet_as/patch.bash b/e2e/assets/greet_as/patch.bash
new file mode 100644
index 0000000000..59b460ad9d
--- /dev/null
+++ b/e2e/assets/greet_as/patch.bash
@@ -0,0 +1 @@
+dfx config canisters/hello/main greet.as
diff --git a/e2e/assets/invalid_as/invalid.as b/e2e/assets/invalid_as/invalid.as
new file mode 100644
index 0000000000..3fba78085a
--- /dev/null
+++ b/e2e/assets/invalid_as/invalid.as
@@ -0,0 +1,4 @@
+Some Invalid Code
+No way this is valid ActorScript, right?
+
+        // Who knows...
diff --git a/e2e/assets/invalid_as/patch.bash b/e2e/assets/invalid_as/patch.bash
new file mode 100644
index 0000000000..515ba2875c
--- /dev/null
+++ b/e2e/assets/invalid_as/patch.bash
@@ -0,0 +1,3 @@
+#!/dev/null
+
+dfx config canisters/hello/main invalid.as
diff --git a/e2e/basic-project.bash b/e2e/basic-project.bash
index e742f52ae7..d95c4fabb4 100644
--- a/e2e/basic-project.bash
+++ b/e2e/basic-project.bash
@@ -1,16 +1,13 @@
 #!/usr/bin/env bats
 
+load utils/_
+
 setup() {
     # We want to work from a temporary directory, different for every test.
     cd $(mktemp -d -t dfx-e2e-XXXXXXXX)
     export RUST_BACKTRACE=1
 
-    dfx new e2e-project
-    test -d e2e-project
-    test -f e2e-project/dfx.json
-    cd e2e-project
-
-    echo PWD: $(pwd) >&2
+    dfx_new
 }
 
 teardown() {
@@ -19,45 +16,25 @@ teardown() {
     killall dfx nodemanager client || true
 }
 
-# Create a new project and starts its client in the background.
-dfx_start() {
-    # Bats create a FD 3 for test output, but child processes inherit it and Bats will
-    # wait for it to close. Because `dfx start` leave a child process running, we need
-    # to close this pipe, otherwise Bats will wait indefinitely.
-    dfx start --background 3>&-
-}
-
-# Takes a name of the asset folder, and copy those files to the current project.
-install_asset() {
-    ASSET_ROOT=${BATS_TEST_DIRNAME}/assets/$1/
-    cp -R $ASSET_ROOT/* .
-}
-
 @test "build + install + call + request-status -- greet_as" {
     install_asset greet_as
     dfx_start
     dfx build
-    INSTALL_REQUEST_ID=$(dfx canister install 1 build/greet.wasm)
+    INSTALL_REQUEST_ID=$(dfx canister install 1 canisters/greet.wasm)
     dfx canister request-status $INSTALL_REQUEST_ID
 
-    run dfx canister query 1 greet --type=string Banzai
-    [[ $status == 0 ]]
-    [[ "$output" == "Hello, Banzai!" ]]
+    assert_command dfx canister query 1 greet --type=string Banzai
+    assert_eq "Hello, Banzai!"
 
     # Using call --wait.
-    run dfx canister call --wait 1 greet --type=string Bongalo
-    echo $output
-    [[ $status == 0 ]]
-    [[ "$output" == "Hello, Bongalo!" ]]
+    assert_command dfx canister call --wait 1 greet --type=string Bongalo
+    assert_eq "Hello, Bongalo!"
 
     # Using call and request-status.
-    run dfx canister call 1 greet --type=string Blueberry
-    [[ $status == 0 ]]
-
+    assert_command dfx canister call 1 greet --type=string Blueberry
     # At this point $output is the request ID.
-    run dfx canister request-status $output
-    [[ $status == 0 ]]
-    [[ "$output" == "Hello, Blueberry!" ]]
+    assert_command dfx canister request-status $output
+    assert_eq "Hello, Blueberry!"
 }
 
 @test "build + install + call + request-status -- counter_wat" {
@@ -105,36 +82,34 @@ install_asset() {
     install_asset counter_as
     dfx_start
     dfx build
-    dfx canister install 1 build/counter.wasm
+    dfx canister install 1 canisters/counter.wasm --wait
+
+    assert_command dfx canister call 1 read --wait
+    assert_eq "0"
+
+    assert_command dfx canister call 1 inc --wait
+    assert_eq ""
 
-    run dfx canister call 1 read --wait
-    [[ "$output" == "0" ]]
-    run dfx canister call 1 inc --wait
-    [[ "$output" == "" ]]
-    run dfx canister query 1 read
-    [[ "$output" == "1" ]]
+    assert_command dfx canister query 1 read
+    assert_eq "1"
 
     dfx canister call --wait 1 inc
-    run dfx canister query 1 read
-    [[ "$output" == "2" ]]
+    assert_command dfx canister query 1 read
+    assert_eq "2"
 
     dfx canister call --wait 1 inc
-    run dfx canister query 1 read
-    [[ "$output" == "3" ]]
+    assert_command dfx canister query 1 read
+    assert_eq "3"
 
-    run dfx canister call 1 inc
-    [[ $status == 0 ]]
-    dfx canister request-status $output
-    [[ $status == 0 ]]
+    assert_command dfx canister call 1 inc
+    assert_command dfx canister request-status $output
 
     # Call write.
-    run dfx canister call 1 write --type=number 1337 --wait
-    [[ $status == 0 ]]
+    assert_command dfx canister call 1 write --type=number 1337 --wait
+    assert_eq ""
 
     # Write has no return value. But we can _call_ read too.
-    run dfx canister call 1 read
-    [[ $status == 0 ]]
-    run dfx canister request-status $output
-    [[ $status == 0 ]]
-    [[ "$output" == "1337" ]]
+    assert_command dfx canister call 1 read
+    assert_command dfx canister request-status $output
+    assert_eq "1337"
 }
diff --git a/e2e/config.bash b/e2e/config.bash
index d8336f48df..dcc5fb3584 100644
--- a/e2e/config.bash
+++ b/e2e/config.bash
@@ -1,33 +1,29 @@
 #!/usr/bin/env bats
 
+load utils/_
+
 setup() {
     # We want to work from a temporary directory, different for every test.
     cd $(mktemp -d -t dfx-e2e-XXXXXXXX)
+
+    dfx_new
 }
 
 @test "dfx config -- read/write" {
-    dfx new e2e-project
-    cd e2e-project
-
-    run dfx config defaults/build/output
-    [[ $status == 0 ]]
-    [[ "$output" == "\"canisters/\"" ]]
+    assert_command dfx config defaults/build/output
+    assert_eq '"canisters/"'
 
-    run dfx config defaults.build.output
-    [[ $status == 0 ]]
-    [[ "$output" == "\"canisters/\"" ]]
+    assert_command dfx config defaults.build.output
+    assert_eq '"canisters/"'
 
-    run dfx config defaults/build/output "other/"
-    [[ $status == 0 ]]
+    assert_command dfx config defaults/build/output "other/"
+    assert_eq ""
 
-    run dfx config defaults/build/output
-    [[ $status == 0 ]]
-    [[ "$output" == "\"other/\"" ]]
+    assert_command dfx config defaults/build/output
+    assert_eq '"other/"'
 
-    run dfx config non_existent
-    [[ $status == 255 ]]
+    assert_command_fail dfx config non_existent
 
     # We don't allow to change values that are non existent.
-    run dfx config non_existent 123
-    [[ $status != 0 ]]
+    assert_command_fail dfx config non_existent 123
 }
diff --git a/e2e/frontend.bash b/e2e/frontend.bash
index 8a8af506b1..e01fc69dcf 100644
--- a/e2e/frontend.bash
+++ b/e2e/frontend.bash
@@ -1,11 +1,12 @@
 #!/usr/bin/env bats
 
+load utils/_
+
 setup() {
     # We want to work from a temporary directory, different for every test.
     cd $(mktemp -d -t dfx-e2e-XXXXXXXX)
 
-    dfx new e2e-project
-    cd e2e-project
+    dfx_new
 }
 
 teardown() {
@@ -14,35 +15,19 @@ teardown() {
     killall dfx nodemanager client || true
 }
 
-# Creates a new project and starts its client in the background.
-dfx_start() {
-    # Bats create a FD 3 for test output, but child processes inherit it and Bats will
-    # wait for it to close. Because `dfx start` leaves a child process running, we need
-    # to close this pipe, otherwise Bats will wait indefinitely.
-    dfx start --background $* 3>&-
-}
-
-# Takes a name of the asset folder, and copy those files to the current project.
-install_asset() {
-    ASSET_ROOT=${BATS_TEST_DIRNAME}/assets/$1/
-    cp -R $ASSET_ROOT/* .
-}
-
 @test "dfx start serves a frontend" {
     dfx_start
 
-    run curl http://localhost:8000 # 8000 = default port.
-    [[ $status == 0 ]]
-    grep -i "<html>" <(echo $output)
+    assert_command curl http://localhost:8000 # 8000 = default port.
+    assert_match "<html>"
 }
 
 @test "dfx start serves a frontend on a port" {
     dfx_start --host 127.0.0.1:12345
 
-    run curl http://localhost:12345 # 8000 = default port.
-    [[ $status == 0 ]]
-    grep -i "<html>" <(echo $output)
+    assert_command curl http://localhost:12345 # 8000 = default port.
+    assert_match "<html>"
 
-    run curl http://localhost:8000
-    [[ $status != 0 ]]  # This should have failed (no frontend on 8000).
+    assert_command_fail curl http://localhost:8000
+    assert_match "Connection refused"
 }
diff --git a/e2e/utils/_.bash b/e2e/utils/_.bash
new file mode 100644
index 0000000000..4d083d9922
--- /dev/null
+++ b/e2e/utils/_.bash
@@ -0,0 +1,28 @@
+source ${BATSLIB}/load.bash
+load utils/assertions
+
+# Takes a name of the asset folder, and copy those files to the current project.
+install_asset() {
+    ASSET_ROOT=${BATS_TEST_DIRNAME}/assets/$1/
+    cp -R $ASSET_ROOT/* .
+
+    [ -f ./patch.bash ] && source ./patch.bash
+}
+
+dfx_new() {
+    dfx new e2e-project
+    test -d e2e-project
+    test -f e2e-project/dfx.json
+    cd e2e-project
+
+    echo PWD: $(pwd) >&2
+}
+
+# Start the client in the background.
+dfx_start() {
+    # Bats create a FD 3 for test output, but child processes inherit it and Bats will
+    # wait for it to close. Because `dfx start` leave a child process running, we need
+    # to close this pipe, otherwise Bats will wait indefinitely.
+    dfx start --background "$@" 3>&-
+}
+
diff --git a/e2e/utils/assertions.bash b/e2e/utils/assertions.bash
new file mode 100644
index 0000000000..616c6a2072
--- /dev/null
+++ b/e2e/utils/assertions.bash
@@ -0,0 +1,83 @@
+#!
+
+# Asserts that a command line succeeds. Still sets $output to the stdout and stderr
+# of the command.
+# Arguments:
+#   $@ - The command to run.
+# Returns:
+#   none
+assert_command() {
+    run "$@"
+    [[ $status == 0 ]] || \
+        (  (echo "$*"; echo "$output" | batslib_decorate "Output") \
+         | batslib_decorate "Command failed" \
+         | fail)
+}
+
+# Asserts that a command line fails. Still sets $output to the stdout and stderr
+# of the command.
+# Arguments:
+#   $@ - The command to run.
+# Returns:
+#   none
+assert_command_fail() {
+    run "$@"
+    [[ $status != 0 ]] || \
+        (  (echo "$*"; echo $output | batslib_decorate "Output") \
+         | batslib_decorate "Command succeeded (should have failed)" \
+         | fail)
+}
+
+# Asserts that a string contains another string, using regexp.
+# Arguments:
+#    $1 - The regex to use to match.
+#    $2 - The string to match against (output). By default it will use
+#         $output.
+assert_match() {
+    regex=$1
+    if [[ $# < 2 ]]; then
+        text=$output
+    else
+        text=$2
+    fi
+    [[ "$text" =~ "$regex" ]] || \
+        (batslib_print_kv_single_or_multi 10 "regex" "$regex" "actual" "$text" \
+         | batslib_decorate "output does not match" \
+         | fail)
+}
+
+# Asserts that two values are equal.
+# Arguments:
+#    $1 - The expected value.
+#    $2 - The actual value.
+assert_eq() {
+    expected=$1
+    if [[ $# < 2 ]]; then
+        actual=$output
+    else
+        actual=$2
+    fi
+
+    [[ "$actual" == "$expected" ]] || \
+        (batslib_print_kv_single_or_multi 10 "expected" $expected "actual" $actual \
+         | batslib_decorate "output does not match" \
+         | fail)
+}
+
+# Asserts that two values are not equal.
+# Arguments:
+#    $1 - The expected value.
+#    $2 - The actual value.
+assert_neq() {
+    expected=$1
+    if [[ $# < 2 ]]; then
+        actual=$output
+    else
+        actual=$2
+    fi
+
+    [[ "$actual" != "$expected" ]] || \
+        (batslib_print_kv_single_or_multi 10 "expected" $expected "actual" $actual \
+         | batslib_decorate "output does not match" \
+         | fail)
+}
diff --git a/nix/e2e-tests.nix b/nix/e2e-tests.nix
index 576010ec03..764f53b477 100644
--- a/nix/e2e-tests.nix
+++ b/nix/e2e-tests.nix
@@ -6,12 +6,19 @@
 ,   stdenv
 ,   killall
 }:
+let batslib = builtins.fetchGit {
+    url = "ssh://git@github.com/ztombol/bats-support";
+    ref = "0.3.0";
+    rev = "24a72e14349690bcbf7c151b9d2d1cdd32d36eb1";
+}; in
 
 runCommandNoCC "e2e-tests" {
-    buildInputs = [ bats coreutils curl dfinity-sdk.packages.rust-workspace-debug stdenv.cc killall ];
+    buildInputs = [ bats batslib coreutils curl dfinity-sdk.packages.rust-workspace-debug stdenv.cc killall ];
 } ''
     # We want $HOME/.cache to be in a new temporary directory.
-    HOME=$(mktemp -d -t dfx-e2e-home-XXXX)
+    export HOME=$(mktemp -d -t dfx-e2e-home-XXXX)
+    # We use BATSLIB in our scripts to find the root of the BATSLIB repo.
+    export BATSLIB="${batslib}"
 
     # Timeout of 10 minutes is enough for now. Reminder; CI might be running with
     # less resources than a dev's computer, so e2e might take longer.